Guide - How to wire up thermofans

[The Witzl]

This if for all the people who keep asking... ;)

The Witzl's Guide to Wiring up thermofans

well here you are....

Note regarding thermoswitches: Most toyota thermoswitches i have tested are norally closed type.... meaning that they are connected to earth until they reach a set temperature and then open that connection..... thus if you unplug the wire to the thermoswitch the fan will begin to operate. This is a failsafe for if your switch dies on the inside it will just run the fans permanently....

You can use an aftermarket thermoswitch, just make sure its a normally closed type for wiring it up in this method i am outlining.


Version modified by Mos (acknowledged by Witzl).
http://www.toymods.net/mos/img/fans/Witzl%20thermofan.JPG

And here is the less technical diagram, courtesy of Witzl Inc Graphic Design Studios (aka "TA-022" - Nathan)
http://users.tpg.com.au/nbdean/thermodiagram.png


This is an example of a Toyota Thermoswitch with the blue wire coming out. Found VERY commonly in wreckers in SV21, SV11, AE82, AE92, ST162 etc etc


http://img141.echo.cx/img141/8563/dsc01983copy5rw.jpg


Additional information by Mos:
Below are the standard relays commonly available - all have pins 85 and 86 as the solenoid, and applying power across those pins activates the relay.
The first is a 4 pin, normally open type, with an input on pin 30 and a single ouput on pin 87.
The second is a 5 pin, normally open type, with an input on pin 30 and two outputs on two pins marked 87.
The third is a switching or "change over" 5 pin, with an input on pin 30, a normally closed output on pin 87a and a normally open output on pin 87. Sometimes the "a" is printed away from the 87 and is not immediately obvious.

http://www.toymods.net/mos/img/fans/Standard%20Relays.JPG

A setup using a Normally Closed thermostat should be something like this:
http://www.toymods.net/mos/img/fans/Fan%20Wiring%20NC.JPG

A setup using a Normally Open thermostat is a lot simpler than a NC setup:
http://www.toymods.net/mos/img/fans/Fan%20Wiring%20NO.JPG


*** Mos additions verified by Witzl. Thanks Mos :)

[bbaacchhyy]

Witz,

I have managed to complete my thermo fan wiring, and ended up using a switch that is normally open, and whilst there are several options out there, they are either expensive or on rare vehicles. The one that was best suited was from an Avalon, but sadly, they are over $100 a pop and there aren't many at the wreckers.

My wiring was similar to the above but reflects the different thermos witch used, but your guide was agreat help !!!

Cheers

Michael B

[ed_jza80]

ive got a few variations on witzl's one...

first up, i run my switch on the rad bottom tank/outlet: i think its wiser to have the fans switched on and off based on how the radiator is performing - not on what the output temp of the engine is. after all, isnt the fan supposed to assist the radiator function? and what better way to measure it? if the output temp of the engine is too high, and you know the raditator is working properly (+- fan assist), then theres something wrong with the cooling system, not the way you switch your fans on and off...

anyway, to do this is use a normally open 2 wire thermo switch, as is easily sourced from the bottom rad tank of practically any 90's mitsu magna. on at 85 and off at 75 if i remember correctly

secondly, if i run two fans, i run them on two independant circuits, with their own relays etc, just incase sommething fucks itself

and finally, i run a thermoswitch override switch inside the cabin, so if everything goes to hell for some reason, i can still manually switch the fans on and bypass all wiring.

cheers
ed

[bbaacchhyy]

I sorta agree with you there Ed, but isn't it interesting that most of the manufacturers don't do it this way ? I'll ask the HVAC guys next time I get a chance.

I have the fans wired to separate relays, and will add the cabin switch as you mention. Might even use the A/C switch for this very purpose !!!

Cheers

Michael B

PS The GTO fans are wired such that they can either have one or both switched on - controlled by the ECU.

[Mos]

The above setups don't take into account running A/C for those of us who choose to retain some comfort :p It would take a great deal of time for the water temp switch to "see" the rise in refrigerant pressure due to insufficient air flow. The A/C high pressure switch could be run in series with the water temp switch to allow some fan functionality for the A/C.
The "traditional" toyota setup involving two fans runs the fans in series at low speed when the A/C is activated and the radiator is under temperature. If either the A/C high pressure switch activates, or the radiator temp switch activates, the fans run at full speed in parallel.
The setup usually has a single common supply relay (usually the engine main relay) with two individual relays controlling the switch on for both fans. The fourth relay activates the parallel function.
It would be interesting to find out the relationships between the temperatures at the four possible cooling system locations where one might insert a temperature sensor. Are there any toyotas with this sensor in the top side?
Mos.

[Steve-AE86]

is it just me, or does the 'thermostat' in the top pic look like a bong? :s

[oldcorollas]

is it just me, or does the 'thermostat' in the top pic look like a bong? :s
might just be you.....

anyway,
http://members.optushome.com.au/mkhala/red_celica/pdfs/relay_diags.pdf

not as elegant as witzl design, but simpler.

[wagonist]

Mos, have you got a wiring diagram for the circuit as you've described?

Can it be used like this for aftermarket fans, or is it Toyota only?

[BradW]

might just be you.....

anyway,
http://members.optushome.com.au/mkhala/red_celica/pdfs/relay_diags.pdf

not as elegant as witzl design, but simpler.

Those diagrams appear to be for thermoswitches that close circuit when the "high" temperature is reached (ie normally open) whereas the toyota thermoswitches are, as The Witzl stated, normally closed and go open circuit when temp is "high".
Also it shows the 87a terminal as n/o when 87a is a n/c contact.
Sorry to be picky :p . They are simpler though ;) .

[Mos]

Mos, have you got a wiring diagram for the circuit as you've described?

Yes, I do, but not online unfortunately. I'll try to get something scanned but it won't be a priority I'm sorry.

Can it be used like this for aftermarket fans, or is it Toyota only?

You can use it on aftermarket fans also, although if they're heavily mismatched you can get unpredictable effects. The two aftermarket fans on the sprinter were wired in such a fashion.

Mos.

[Mos]

Those diagrams appear to be for thermoswitches that close circuit when the "high" temperature is reached (ie normally open) whereas the toyota thermoswitches are, as The Witzl stated, normally closed and go open circuit when temp is "high".

Interestingly enough, in contrast to the majority of earlier toyota thermo switches, the IS200 uses normally open switches, ie they connect to activate the fans. I wonder if that's representative of the newer models.

Also it shows the 87a terminal as n/o when 87a is a n/c contact.
Sorry to be picky :p . They are simpler though ;) .

Given that the terminal labelled 87a goes to an indicator light I'd say it should actually be labelled as 87 rather than being a n/c contact. The "standard" 5 pin relays are available with two 87 pins for appropriate applications rather and an 87 and an 87a - the relay pinout appears to be confirm this.

And yeah, much simpler :p

Mos.

[bbaacchhyy]

Well, I have finally gotten on to the HVAC dude, and had an interesting conversation regarding the good bits about the cooling systems and thermofan theory and some of the current trends.

First off, as discussion on the placement of the thermofan switch. Typically, it is now done from the Eng coolant temp sensor and a signal is sent from the ECU rather than a separate switch. Whilst the theory of what Ed mwentioned is OK, the time lag experienced would be minimal. As an example, a V6 Crumpledore, the coolant flow rate through the CRFM is between 20 l/min (idle) to 180 l/min (flat knackers) with a typical flow of 80 l/min. So you can see that even if the thermo switch is on the clod side, the time lag is not that great. Whether it works better or not is another thing. That is the design that most companies use.

New developments though is the shift for the thermostat to be on the cold side of the engine. The reasoning is apparently better engine temp control, but introduces a number of headaches into the system. The coolant temp sensor is still on the hot side. This is the path being chosen by GM and Ford and others, and one of the side aspects is that there is a need for a pressurised surge tank to aid in the filling and degassing of the systems based on the thermostat location. The system fill in plant is done by sucking air out of the systems, and then forcing in coolant (set volume) under pressure to ensure that all (or most) of the air is taken out of the system.

The next thing is about how a set of twin thermo fans should be setup, and what the idea/temps behind the temp switches that control them, but that will be another post when I have a few more moments.

Cheers
For now

Michael B

[The Witzl]

I am considering the use of a PWM speed controlled thermofan on the RA28's 18RG, using a temp sensor with a suitable temp range/output to somehow act as an input to the fan speed controller.

Of course this is silly and completely not worth the effort... but then again i am a silly kind of guy!

[bbaacchhyy]

More as promised.......

OK, now for part two.

I am waiting on some info from the HVAC dude, but I got some interesting stats regarding the temps at what you switch on the fans at. Largely they back up previous numbers quoted in other discussions, but basically the values are such.

For fans running single speed (twins or singles) : Aim for a “temp on” temperature about 10 degrees above thermostat open, and a ”temp off” temperature of 5 degrees above the thermostat temp. This way, you allow for hysteresis of the various temp controlled items, and you also don’t end up with the fans and the thermostat fighting each other at a switch over temp.

For fans running twin speed (twins thermo’s ala AU Ford etc) : The basic set-up is to have the fans run in two modes – Low power and High power. This can be done in a few ways, but the Ford and Holden version is similar (I’m waiting to get the cct details so that I can share this info). The low power setting involves running the two fans together in series which means that both fans only see 6V and therefore only give about 35% of their cooling capacity. With the fans run in parallel, both see 12V, and give 100% cooling capacity.

The switch set-up is that you either run two switches or use a switch that has both internal contacts in it (apparently the JD Vectra has this set-up as do others). For a thermostat of 90 degrees, the low power switch would have the same temps as listed above (fans on at 10 deg above thermostat, and off at 5 deg above thermostat), and for the high power setting, you would have an on temp of 110 degrees and off at 105 degrees, and this allows for a 5 degree hysteresis once again.

The High/Low power set-up is best for DD cars, whilst if the car is an occasional fanger, it is not so important. Part of the main basis for the high/low fan speeds is that when the temps rise and the fans switch on, the engine doesn’t see a huge slug of cold(er) water and then shut the thermostat and you end up with a bit of temperature hunting, but instead you get a gradual cooling that keeps the temperature much more stable.

As soon as I get the info, I’ll try and post it up.

All makes sense to me

Cheers
For now, again

Michael B

[CrUZida]

A lot of the above has seemed to gone over the top (as most tend to do on Toymods).

In my setup, I have a Tridon temp switch (95on, 90off), that switches a Nissan relay (two independant in/outs with a single switch), and the AU thermo's.

Since I have auto, and am running an auto cooler (not the radiator one), I found it was getting very warm at idle after I went from viscous fan to the thermo's.
So I installed an old MA61 aircon fan infront of the auto cooler, which is TPS switched.
When the TPS is in IDL, the fan is on, when the TPS is anywhere else, the fan is off.

This ensures that the tranny cooler is getting moving air at all times while the car is stationary.
Also, thus far, this small amount of air has been enough to keep the motor below 95deg where the thermo's kick in, as they haven't turned on at all in the last few months.

Will be interesting to see how it goes in summer, but I am now confident that I can sit at traffic lights in gear on a 40+degC day and not have any cooling issues.

Aircon is not plumbed yet (its coming) so I don't know how that will go, but I suspect the auto cooler fan I've installed will help there.

[The Witzl]

i'm going to be installing a temporary digital display of the coolant temperature in the crown... because im really interested to see just how stable it keeps the temps with all the acilliaries on that car.

[bbaacchhyy]

A lot of the above has seemed to gone over the top (as most tend to do on Toymods).

.

I'm not sure what you menat by that ?

The info above was just some data of what they do for production cars, and whilst it is more complex, car companies don't spend money for things they don't have to.

Personally, I'll 99% stick with my setup (both fans come on at once), but I'll look into the data once I get it.

If it is not too hard to rewire, i may do it, but letting the temp get to 110 degrees is a bit scary for me.

Anyways, food for thought

Cheers

Michael B

[wagonist]

Yes, I do, but not online unfortunately. I'll try to get something scanned but it won't be a priority I'm sorry.

You can use it on aftermarket fans also, although if they're heavily mismatched you can get unpredictable effects. The two aftermarket fans on the sprinter were wired in such a fashion.

Mos.
I'll try to organise a time to come over & get a copy then.
I'll be running 2 identical aftermarket fans, but I like the idea of running them slower when its not necessary.
The Subaru factory fans for the ECU I'm running have 3 wires on them for half speed running (but these fans won't fit in my installation) & the ECU controls the fans anyway from a temp sensor which is in the feed pipe to the block.

[TurboRA28]

Cruzida, you wouldn't happen to have part number of that tridon switch would you? I've been hunting around for ages and all I've come up with is a 85on, 80off switch. This is too low. 95/90 sounds perfect.

Cheers
Joel

[CrUZida]

Ummm, sorry. I don't have it on me, but I may have it at home.

Go to somewhere that has the catalogue, there is about 50 to choose from.
All different temps, different threads, different pins (some 1, some 2, some 3)

Mine was a 14x1.5 from memory, I'll try and dig it up at home.

[bbaacchhyy]

Do as CrUZsida suggests, but also check the prices. They can vary from $40 to $150 for something that does the same job.

I ended up using one from a Nissan Prairie !!!

[CrUZida]

Mines from a BMW of sorts.
But yes, Bbaacchhyy is right, they do vary in price.
I'm not sure if its quite the range he said, but the one I got was about $70 retail, $50 trade.

[bbaacchhyy]

The Tridon one I got for the Priarie was $56, the Avalon one was $110 for the Tridon and $160 for the Toyota one.

Mind you, I was only looking at ones with M16 thread and had to be low protrusion into the rad tank due to the rad design, so that may have had siome influence on cost.

Cheers

Michael B

[bbaacchhyy]

Below are some numbers as promised


As discussed yesterday, here is a bunch of info on VY Cooling fan control.


Inst. Cluster "Hot Chime" at 118 degC

VY V6 A/C Clutch: "Cut Out" 119
"Cut In" 115

VY V6 Rad Fan Temps: "Low Fan" ON= 104 OFF= 99.5
"High Fan" ON= 107 OFF= 103

VY V6 Thermostat Temps: "Nominal" 91 degC
"Fully Open" 104 degC

And now, here is a cct for high low fan speed setups that has been modified to suit mechanical switches. It was used by Ford for their bosch fans up to BA, and similar to VE.

http://img137.imageshack.us/img137/8493/serparfancircuit0jd.png (http://imageshack.us)

Some other comments from the guy ;

It requires 3 relays in total, I've shown the P/N's for Holden VY/VZ fan relays which are well suited to fan motor loads. You need good quality high current relays, terminals & cable for cooling fans as they suck a lot of current (typically 20 amps per motor) & can burn wires/terminals or loose fan performance due to voltage drop. Also, you often need to upgrade your Alternator when you fit Electric Cooling Fans, people usually overlook this. Additionally, make sure that there is absolutely no electrical connection to the coolant circuit through your fan wiring as this can cause severe corrosion of the cooling system parts. Basically, this means the temp switches & fan motors must not ground through the radiator or coolant, they should be electrically isolated from the coolant, hoses & radiator.

I have highlighted a particular point in the blub above, as it was not something that I had thought about, but will make sure that I will do it. Fortuneatley, the thermofan switch that I got does not earth with the switch body, so a bit of good luck there.

Any further input from the other knowledgable people out there ?

Cheers

Michael B

[bbaacchhyy]

Below are some numbers as promised


As discussed yesterday, here is a bunch of info on VY Cooling fan control.


Inst. Cluster "Hot Chime" at 118 degC

VY V6 A/C Clutch: "Cut Out" 119
"Cut In" 115

VY V6 Rad Fan Temps: "Low Fan" ON= 104 OFF= 99.5
"High Fan" ON= 107 OFF= 103

VY V6 Thermostat Temps: "Nominal" 91 degC
"Fully Open" 104 degC

And now, here is a cct for high low fan speed setups that has been modified to suit mechanical switches. It was used by Ford for their bosch fans up to BA, and similar to VE.

http://img137.imageshack.us/img137/8493/serparfancircuit0jd.png (http://imageshack.us)

Some other comments from the guy ;

It requires 3 relays in total, I've shown the P/N's for Holden VY/VZ fan relays which are well suited to fan motor loads. You need good quality high current relays, terminals & cable for cooling fans as they suck a lot of current (typically 20 amps per motor) & can burn wires/terminals or loose fan performance due to voltage drop. Also, you often need to upgrade your Alternator when you fit Electric Cooling Fans, people usually overlook this. Additionally, make sure that there is absolutely no electrical connection to the coolant circuit through your fan wiring as this can cause severe corrosion of the cooling system parts. Basically, this means the temp switches & fan motors must not ground through the radiator or coolant, they should be electrically isolated from the coolant, hoses & radiator.

I have highlighted a particular point in the blub above, as it was not something that I had thought about, but will make sure that I will do it. Fortuneatley, the thermofan switch that I got does not earth with the switch body, so a bit of good luck there.

Any further input from the other knowledgable people out there ?

Cheers

Michael B

[Cuzzo]

Sorry to bring this up but should this be in FAQ?

[The Witzl]

it's already in the FAQ iirc, but not with the extra posts that have been made here.

I'd love to do some topic merging, but need some improvements to the front end moderating controls first :)

[Robbos_Toyotas]

you also need to mention, in the setup, you need two different sorts of 5 pin relays, a dual way 87, and a single circuit 87.

[ProjectSleeper]

If I can chime in and say that on my 2JZ (running twin 14" thermos) I am running twin relays that are switched by the Jaycar "Universal Voltage Switch" I get the signal from the Gauge Temp probe and have them turn on and off based on the signal (voltage) recieved from the factory probe. I also run a tiny led on the dash that illuminates when they are running so I can tell (as they are very quiet and almost impossible to tell once the engine is running...

No need for a "over-ride" switch as I can easily switch them on at the relays if there is any problems with them not turning on..

Jaycar link...
http://www.jaycar.com.au/productView.asp?ID=KC5377&CATID=25&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=347

[Tom86]

I just wired up my Thermo on the weekend. The Witzl diagram would have save me alot of time:mad: . Anyway I ended up using a mechanical switch with copper probe, doesn't look as neat but does the job and I can set the fan to come on anywhere between 40-120 degrees.

What would be a good switch on temp for a stock 4agze? I currently have mine set at 80degrees.

[Fish]

95 degree's turn on and turn off at 82?

[The Witzl]

If I can chime in and say that on my 2JZ (running twin 14" thermos) I am running twin relays that are switched by the Jaycar "Universal Voltage Switch" I get the signal from the Gauge Temp probe and have them turn on and off based on the signal (voltage) recieved from the factory probe. I also run a tiny led on the dash that illuminates when they are running so I can tell (as they are very quiet and almost impossible to tell once the engine is running...

No need for a "over-ride" switch as I can easily switch them on at the relays if there is any problems with them not turning on..

Jaycar link...
http://www.jaycar.com.au/productView.asp?ID=KC5377&CATID=25&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=347


Southo done good here :)

[SillyCarS]

ALSO!

Dont foret if you run two fans make sure you wack some diodes in, as this will stop any 'back feeding' of the voltage between the high and low speed fans and cause them either to lock or not operae at all. This is normal as with two fans you will want to bridge both the fan relays together, this insures the will both come on as early as possible and both drive a a constant speed

[Robbos_Toyotas]

and another thing, take note of the operation of the switch. Toyota are almost the only manufacturer to make a "normally closed" one, so the output to the fan on the relay will vary depending on this.

[bansheebuzz]

sorry dont worry was not supposed to post

[Mos]

ALSO!

Dont foret if you run two fans make sure you wack some diodes in, as this will stop any 'back feeding' of the voltage between the high and low speed fans and cause them either to lock or not operae at all. This is normal as with two fans you will want to bridge both the fan relays together, this insures the will both come on as early as possible and both drive a a constant speed
Are you serious?
Not sure what you're trying to say here, but I haven't seen any fans that would need that.
I think you might mean that the fans have two windings, one for low speed and one for high speed, in which case you would need to make sure you don't feed both windings are the same time - this is not the case with any fans that I have seen used in automotive applications, and I'm pretty sure none of the fans discussed in this thread are of this type.

The low speed / high speed modes are effected by running the two fans in series for low speed (so each fan is supplied 6-7V), and conventional parallel operation at high speed (each fan gets 12-14V).

The suggested diodes would need at least 20A current handling, something which is only commonly available in a large bridge rectifier rather than individual diodes, but as said above, they're not needed in my experience.

and another thing, take note of the operation of the switch. Toyota are almost the only manufacturer to make a "normally closed" one, so the output to the fan on the relay will vary depending on this.
I used to think this was a toyota standard (NC temperature switches), until I saw the IS200 diagrams - the temperature switch is a normally open type, so it's possible more modern toyotas will vary.

Mos.

[PULSE]

Hey guys, sorry for bringing up an old thread and asking a noob question but would someone be able to tell me what relays to ask for when I go into jaycar. Also what size fuse should I be using between the battery and relay?

Cheers, Matt

[takai]

SPDT or "Horn" relays.

[PULSE]

I bought 2 horn relays the other day, one was to use as my EFI relay, the other was meant to be for this (thought I only needed one), but they are only 4 pin, not 5 pin as in the diagram?

[Cuts]

hey all interesting read.

since a number of you are more electronically minded then me i thought i could ask you chaps a question.
the thermofans in the 205 have stopped working properly, they switch as they are supposed to but the fans go around at about 5 rpm (both fans come on togther), the fans are fine, the temp sensor is fine, at the moment i ran new relays and wiring for the thermo fans but if possible ide like to have it back to the neater stock setup.

any thoughts on why they would be turning so damm slow? earthing problem? Me and a mate tested one of the fan outputs and i seem to remember the voltage dropping from 12 straight to around 2 or 3 when it was on load, hence the slow turning i suppose.

Im 99% sure the relays are firing as they are supposed to.

cheers in advance.

[VA61DETT]

Cuts, Did your new relay setup work ok?
If so then it most likely would be the factory relays are stuffed / contacts burnt perhaps?
You may be able to disassemble them and clean the contacts, but best to replace.
Should be able to measure a very low <1(ohm) resistance to ground on one of the fan plugs (from car side)
this may not always be the case if there is some fancy speed control circuit, not too familiar with pug wiring.

I just finished installing one of the jaycar voltage switch kits on my MA61, works a treat with the factory temp sensor,
also modified it to allow staged switching of 2 fans (using leftover op-amp), to help with sudden inrush current.
If anyone is interested I can post the whole setup + pics & circuit diagrams.

-A

[LeeRoy]

anyway, to do this is use a normally open 2 wire thermo switch, as is easily sourced from the bottom rad tank of practically any 90's mitsu magna. on at 85 and off at 75 if i remember correctly

secondly, if i run two fans, i run them on two independant circuits, with their own relays etc, just incase sommething fucks itself
Is a 2 wire thermoswitch wired up differently to a single wire one? and how do the 2 wire versions work?

[Cuts]

va16 yeah my new relay setup works fine, but its just masking the problem.
we did test voltages on the relays contacts in the fusebox, and relay one can fire relay 2 and 3 like its supposed to.
see the thing is the fans turn on and off when they are supposed to but they are only just going around, not at full speed like Mr T intended wayyy back in 94.

[PULSE]

I got a few relays and a fuse holder so I'm going to have a go at wiring it up today. I'm still not 100% on a few things, first of all, what size fuse should I be using? In the diagram is the top pin the one closest to the front of the relay(ie the part with the writing/diagram on it)? Theres another image in the original post that doesn't load anymore, has anyone saved it?

Thanks guys!

[VA61DETT]

Cuts - Still sounds like your origional relays are flakey to me, they may be turning on but the 'on' resistance of the contacts may be high, hence the large volt drop on the fan side.
Could also be fan fuses / holders having contact issues, are you able to swap out the fan relays with some other ones, or may be just bridge the contactor socket with a bit of wire (as a test).

-A

[Mos]

I got a few relays and a fuse holder so I'm going to have a go at wiring it up today. I'm still not 100% on a few things, first of all, what size fuse should I be using? 20, 25, 30A Toyota uses 30A (each) for fans that draw around 6-7A continuously. Fuse each fan individually and use individual relays. Even though the 6.4mm spade connectors are nominally rated at 15A, one such connector generally will not handle two fans (12-14A) in the long run.
Fuses are there to protect wiring against short circuits, so the exact rating of the fuse is not critical - generally I choose a fuse rating no higher than the thinest cable supplied by that circuit (ie 20A cable, I'll use a 20A fuse, assuming the relay can handle 25A or so, although it's not that critical). You could get a failure mode where the current exceeds the rating of the cable but is within the rating of the fuse - the wire will get hot until it either burns or the fuse blows or you notice it. A straight short circuit will blow the fuse almost instantly, so even a 10A cable won't get very hot before a 30A fuse blows.

In the diagram is the top pin the one closest to the front of the relay(ie the part with the writing/diagram on it)? If I'm thinking of the right one, it's pin 87.
Key points to remember:
1) 85 and 86 are the coil of the relay and as long as you apply power to those it will switch on - it doesn't matter which way around so you don't have to follow the diagrams to the letter.
2) 30 and 87 are the switch, and it doesn't matter which way around you connect it (in certain circumstances it will matter if you have 3 switching pins, ie either 30 and two 87 pins, or 30, 87 and 87a).

Is a 2 wire thermoswitch wired up differently to a single wire one? and how do the 2 wire versions work? It can be. A thermo switch can either connect or disconnect when heated. A single wire switch has to have the body grounded so you would need to use it in the ground path of the relay switching.
A 2 wire sensor can be used in either the ground path or the power path for the relay switching. In practice I think all toyota sensors are in the ground path, regardless of type.

we did test voltages on the relays contacts in the fusebox, and relay one can fire relay 2 and 3 like its supposed to.
see the thing is the fans turn on and off when they are supposed to but they are only just going around, not at full speed like Mr T intended wayyy back in 94. Keep testing. Measure voltage, with the fans running, across every connection - ie measure across the length of wire from the relay to the fan; measure length of wire from fan connector to ground, and relay to ground; measure from battery to both sides of the relay; measure across relay; measure the jumper wire between the two relays. If you're only getting 2-3V on the fans there is a voltage drop somewhere that shouldn't be there (well duh) - you will find it this way.
It could be something as stupid as oxidation on the contacts (replugging the plug usually clears that - have you unplugged everything and plugged it back in?) though with high current circuits it's usually unlikely as the high current burns off the oxidation; it could be corrosion in a crimp, or burnt contacts in the relays, etc.

I just finished installing one of the jaycar voltage switch kits on my MA61, works a treat with the factory temp sensor,
also modified it to allow staged switching of 2 fans (using leftover op-amp), to help with sudden inrush current.
If anyone is interested I can post the whole setup + pics & circuit diagrams. Sure, put it up - I'm sure it will be useful and at worst you'll get +rep for it :p

Mos.

[Cuts]

bump.
still searching for the dramas, but ive been thinking about getting some sort of thermo switch so i can change the on/off temps, as the factory ones are 94/90 i think, ide ideally like say 88 on and 84 off as the thermostat is 77deg.
question is who makes/where can i get such a switch? im not going to use the ghetto thermocouple probe ones, something i could screw into the radiator where the stock thermo fan switch is would be ideal.

suppose if there is a switch thats the temp range im after in another car i could get one of those and wire that in with relays to do the job.

[takai]

http://www.toymods.net/forums/showthread.php?t=5125

See here. Complete listing of Tridon temp senders.

[Cuts]

cheers takai,

[Mos]

bump.
still searching for the dramas
Have you done what I suggested?

[Cuts]

yes and no, ive been through it roughly, ill have another proper crack when i next have some free time, cheers for everyones help so far.

[Mos]

You know there is a diagnostic process, right? Otherwise you're just stumbling on things and you'll only fix it if you get lucky....
If it's too hard, would it be easier to just replace the car? ;)

[Cuts]

what is this diagnostic process?
im assuming you mean with the diagnostics port checking for error codes? i havnt tried because i dont expect that to work.

and the wiring diagram for that particular part of the car is the illusive RM380E which is impossible to find.

[Mos]

The diagnostic process is the process by which you come up with a diagnosis - ie the steps you take to work out the problem.
In this case the diagnostic process is to probe each section of the circuit to find the unwanted voltage drop.
What I took for granted, is *exactly* where to probe when I suggest a diagnostic process... sorry... I guess I just assumed that when I say "the wire from the fan to the relay" you will know what I mean.
The toyota twin thermo setup is virtually identical across the whole range, so you should be able to work out where to probe by looking at the ST185 diagram. It will at least give you an idea of what the layout is and what the relays do, but the wire colours might be slightly different. I think I had some 205 diagrams. I'll see what I can dig up.

[Cuts]

cheers man, when you said about diagnostic i assumed you were talking about grounding pins in the port like you do for engine. and systems checks.

yeah like i said i had a quick test, ill have another crack when i have some time off.

checked the tridon catalogue, that one doesnt have the sensor configuration on it, but one i looked at today at bursons had, there is fuck all on offer for a normally closed switch.
185 and 205 both use normally closed with different plugs, swtich on/off temp is the same, and they list only two on off options for a normally closed with that thread size, 95-90 and 90-85. Factory specs are supposed to be 90-85 apparently but mine seems to be more because according to the pfc its on at around 95 and off at around 90 (from memory) either i have the wrong switch or mine is a little shagged.

[Rosie]

Any reason this isn't used ( the drawing not the part #)
And FYI Champion Part # CFS 40 is 95on 90 off, M14 x 1.5 $50 new from generic places repco etc.

[CrUZida]

Any reason this isn't used ( the drawing not the part #)
You'll find those switches aren't designed to handle large current.

FWIW AU/EL thermo's pull ~15A EACH while running (as will any other decent thermo), and probably 4-6times that on startup for a couple of hundred ms.

[Mos]

Toyota fans tend to draw around 6-7A on a 30A capacity circuit... Haven't measured startup current though...
15A is huge - did you measure that?

[takai]

My twin SPALs on the old car drew >30A as it repeatedly blew 30A fuses.
The DC/DCripoff pair on the Cressy are also >15A each as they blow 15A fuse (i did use 30A wire for each)

[CrUZida]

Toyota fans tend to draw around 6-7A on a 30A capacity circuit... Haven't measured startup current though...
15A is huge - did you measure that?
I haven't personally measured it, but Pete (82MKII) has and from memory it was up around 15A each.
They also managed to severely melt a 25A fuse I had feeding the pair, so that tells me they draw more than 25A (but not enough more to blow the fuse instantly).
The 40A fuse that replaced them was fine.

[chaserbuddy]

hey, i was just wondering if there's anyplace for a thermo switch on 1jz? and im a bit of a noob at this whole electrical wiring stuff what are those black box thingy's and where can i get them?

thanks David

[LeeRoy]

hey, i was just wondering if there's anyplace for a thermo switch on 1jz? and im a bit of a noob at this whole electrical wiring stuff what are those black box thingy's and where can i get them?

thanks David
You could get a thermoswitch from toyota but it would cost you your firstborn most likely.

The black boxes are relays and are mounted in relay holders, both of which are available from repco, supercheap, etc.

[chaserbuddy]

i think ill just go with a switch inside the car somewhere, just switch it on when the car is warm/hot, until i figure something out. 1st post states that they are abundant in wreckers should be able to fit it somewhere in a hose and earth the connector. It was wired up before hand with some type of oven switch haha. :)

[VA61DETT]

Hi

chaserbuddy.

You can always do what I used to do and use one of these to drive you thermo fan relay:
http://www.altronics.com.au/index.asp?area=item&id=S5595

I used to just bolt em on to the thermostat housing with an ally tab.
Good for a quick & cheep solution :D
Just make sure to get the 'Normally Open' type.

-A

[chaserbuddy]

Hi

chaserbuddy.

You can always do what I used to do and use one of these to drive you thermo fan relay:
http://www.altronics.com.au/index.asp?area=item&id=S5595

I used to just bolt em on to the thermostat housing with an ally tab.
Good for a quick & cheep solution :D
Just make sure to get the 'Normally Open' type.

-A
would i be able to get one of these at a local shop, like jaycar or repco/ sprint etc? or will i have to buy from altronics?

cheers

[VA61DETT]

Yer Jaycar have em,

well on the website anyway:
http://www.jaycar.com.au/productView.asp?ID=ST3833&CATID=&keywords=thermal+switch&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=

However they are only 70 degree ones, or 100 degree.
70 is a little cold, 100 is kinda too hot.
you really want 80 - 90 degree ones.
70 would prolly do ok, will at least allow the engine to heat up faster.

The problem with these switches are the hysteresis is way huge, so once they trip the fans
will never turn off under normal driving conditions.

-A

[chaserbuddy]

Hi

Just make sure to get the 'Normally Open' type.

-A

is this a typo or something cos the 1st post says get a normally closed type? ill see if i can get both because there cheap and if ones wrong ill use the other

[LeeRoy]

A normally closed switch will require two relays. The plus side however is that if the switch fails then the fans will automatically kick in, effectively acting as a failsafe. The majority of standard thermoswitches are normally closed.

A normally open switch will only require one relay but if the switch fails then the thermos won't kick in.

[VA61DETT]

Aah Yer I may have stuffed up some where,

You can use either, just means you will need an extra relay
(^ what LeeRoy said)

I have used a NO type setup for about 2 years on my car, till just recently
Now I built one of the jaycar voltage switch kits to get more accurate control over cooling.
(decided to put more effort in since I just rebuilt the motor)

-A

[chaserbuddy]

the thermos wont kick in for some reason, i think its to do with the thermo switch not getting hot enough. i have mounted it onto a small bit of aluminum which is connected to the front/side of the waterpump, just below the two standard water thermostats? this should get easily enough heat...? 70 degrees isn't that much so there's no reason why is shouldn't kick in.

[VA61DETT]

What kind of setup did you end up going with?
Have you tried opening / shorting the thermo switch to test the relays?

I usually mount the sensor close as possible to the thermostat housing on the head.
Though the water pump housing should get hot enough.
The sensor base needs to be secured on a flat surface, if there is an air gap it may not switch.

-A

[chaserbuddy]

same setup as shown on the digram altough the 1st relay is pointless LOL! could just run a wire straight from ignition, also the pin that goes to the thermo switch is in the bottom vertical pin instead of the middle pin i assume witzl fucked that up on the diagram...shorting the thermos switch to earth makes the fans work so its def the thermostat switch, on a flat surface and earthed NC thermo switch also...maybe it doesn't get hot enough also is it supposed to be earthed from the base or is it earthed from one of the two pins at the top, cos i have tried earthing it from a top pin also...but still wont work! god damn cheap switches...

[LeeRoy]

Is the place it is mounted actually grounded? Cause if youve installed it between 2 hoses then it wont ground.

If youve got a normally closed switch and shorting the wire to ground turns the fans on then youve not only wired it up wrong but the fans will be on permanently.

Sure Witzls paint skillz arent fantastic but the diagram is perfect and works equally as well. If you followed it then you wouldnt be here posting about why your fans don't work. The 2 relays are needed because you need to throw the 85a pin to 85 so it doesnt run the fans all the time.

If your using a normally closed switch then this is the only way to do it. A normally open switch can be wired using a single 4 pin relay but lacks the failsafe of turning the fans on if the switch dies.

[Mos]

same setup as shown on the digram altough the 1st relay is pointless LOL! could just run a wire straight from ignition,
Why don't you ask the question rather than making an inaccurate statement?
The first relay is needed because it switches the high current required to run the thermo fan. Sure you can hook it up straight from your ignition switch, but you would need reasonably thick cables from the ignition switch to the second relay (thin cables will also work (for now) - doesn't mean it's right) and you reduce the lifespan of your ignition switch.

If you're going on the dodgy you might as well use the thermostat itself to switch the fan current. The altronics one is rated at 10A, enough for one fan - that way you don't need any relays and saves complications (for now).

also the pin that goes to the thermo switch is in the bottom vertical pin instead of the middle pin i assume witzl fucked that up on the diagram...
I'm sure 4 pages-worth of people didn't pick up the error - thanks for your expertise...

but still wont work! god damn cheap switches...
Yes, blame the switch. Your understanding of how it works is beyond question... *sigh*...

shorting the thermos switch to earth makes the fans work so its def the thermostat switch,
Shorting the thermostat makes the fans turn on? In that case you have wired it up for a NO thermostat...

on a flat surface and earthed NC thermo switch also...
...but yet you say you bought a NC switch?

maybe it doesn't get hot enough also is it supposed to be earthed from the base or is it earthed from one of the two pins at the top, cos i have tried earthing it from a top pin also...
The housing of the thermostat performs only a mechanical and thermal function - the electrical function is performed by the two terminals - so one terminal would go to the relay, the other terminal would go to ground.
Why don't you post photos of what you've done? It will be too hard for us to talk you through it because you're rejecting a correct diagram/solution. You either know, or not, you can't have it both ways.

Mos.

[chaserbuddy]

well it turns out that i got two normally open switches instead of one no and one nc...
this is what i had done...
http://i512.photobucket.com/albums/t329/chaserbuddy/DSC06951copy.jpg
http://i512.photobucket.com/albums/t329/chaserbuddy/DSC06955copy.jpg

wrong switch and relays are not much help, bad luck and knowledge doesn't do anyone any good. sorry for being an annoyance aswell just frustrated because i couldn't figure it out.

also my two original relays show that pins 87 and 87a are not connected which is why they power wasn't going to the fans...these are the three relays, i have 2 of the 1st and one of the second,
http://i512.photobucket.com/albums/t329/chaserbuddy/blah.jpg

I don't think either will work with the method shown by witzl. so i am going to just wire a simple NO setup now instead...

cheers

[Mos]

well it turns out that i got two normally open switches instead of one no and one nc...
That would explain some of it.

this is what i had done...
That should fine, provided that part of the water pump gets hot enough, fast enough. Electrically that should be fine but I would use the crimp spade connectors on these as well.
Only proviso, and I'm sure you know it, is to use black for ground, but obviously it won't stop it from working.

http://i512.photobucket.com/albums/t329/chaserbuddy/DSC06955copy.jpg

wrong switch and relays are not much help, bad luck and knowledge doesn't do anyone any good. sorry for being an annoyance aswell just frustrated because i couldn't figure it out.
Unfortunately what you have hooked up is not correct. I just realised Witzl screwed up the diagram :p I owe you an apology - sorry :) I guess 4 pages of people didn't pick it up... (He didn't screw up where you said he did, but the 2nd relay red wire should go to pin 30 (bottom middle vertical) instead of 87 (top middle horizontal).

The first relay works.
The second relay has both the batt and fan connected to either two pin 87 or one 87 and one 87a depending on what kind of relay you have used. What you should have hooked up is the batt to pin 30 and the fan to pin 87a (87a is correct as long as it's an 87/87a relay).
Being pedantic, and once again won't stop it from working, is that "ign" should be a red wire by convention.

also my two original relays show that pins 87 and 87a are not connected which is why they power wasn't going to the fans...these are the three relays, i have 2 of the 1st and one of the second,
87 and 87a are never connected together, and I have never seen 86/86a in that fashion.
Below are the standard relays commonly available - all have pins 85 and 86 as the solenoid, and applying power across those pins activates the relay.
The first is a 4 pin, normally open type, with an input on pin 30 and a single ouput on pin 87.
The second is a 5 pin, normally open type, with an input on pin 30 and two outputs on two pins marked 87.
The third is a switching or "change over" 5 pin, with an input on pin 30, a normally closed output on pin 87a and a normally open output on pin 87. Sometimes the "a" is printed away from the 87 and is not immediately obvious.

http://www.toymods.net/mos/img/fans/Standard%20Relays.JPG
I don't think either will work with the method shown by witzl. so i am going to just wire a simple NO setup now instead...
Witzl's setup is correct provided the correct relays are used.
Should be something like this:
http://www.toymods.net/mos/img/fans/Fan%20Wiring%20NC.JPG

This circuit operates as follows:
http://www.toymods.net/mos/img/fans/Fan%20Wiring%20NC%20cold.JPGhttp://www.toymods.net/mos/img/fans/Fan%20Wiring%20NC%20hot.JPG


An NO setup will be fine, and is simpler than an NC setup.
http://www.toymods.net/mos/img/fans/Fan%20Wiring%20NO.JPG

This circuit operates as follows:
http://www.toymods.net/mos/img/fans/Fan%20Wiring%20NO%20cold.JPGhttp://www.toymods.net/mos/img/fans/Fan%20Wiring%20NO%20hot.JPG

In your case, replacing the "ground" wire on the first relay with the wire from the thermostat should work.

HTH.
Mos.

[chaserbuddy]

i knew there might have been a mistake somewhere because normally things don't work out this hard haha, thanks for all your help Mos +rep for you :)

[Smokey228]

If your running two fans, does one power cable to to the first fan and then bridge to the next fan aswel? Or do you need more relays?

And mos, on the first relay in the two relay configuration, how come battery power goes to the wire that goes to the second relay? Wouldnt that mean that even when ing is off, the 2nd relay will stay powered? Or am i just wrong :p

Cheers,
Jase

[chaserbuddy]

If your running two fans, does one power cable to to the first fan and then bridge to the next fan aswel? Or do you need more relays?

And mos, on the first relay in the two relay configuration, how come battery power goes to the wire that goes to the second relay? Wouldnt that mean that even when ing is off, the 2nd relay will stay powered? Or am i just wrong :p

Cheers,
Jase

yes bridges to the other fan. i think i can help with the second question aswell when to coil is uncharged i.e ignition off, the switch switches back, stopping the battery power from going though the switch and to the next relay.

[Mos]

Personally I would not bridge a second fan off the same relays. Even though the relays are rated at 20 or 30 Amps, the spade pins are only rated around 15A, and a single relay and base will melt over time with two fans (had it happen). For peace of mind, a single fan per circuit :)

And yes, when you turn the ignition off, the relay solenoid is de-energised and the relay contact opens.

[VA61DETT]

Nice write up Mos!

I was almost about to draw up the cct myself, but was lazey ;p

-A

[Cuzzo]

The good thing about the whitzls diagram aswell as toyota factory, when you remove the plug from the thermo switch on the remote thermo housing (4age ae82) the thermo turns on.

[rogue-vl]

What switch range is everyone using for the 1JZ, I have a 95 on 90 off, the engine at idle runs at 96-98 so the fans never switch off, maybe i have the wrong range, maybe there is an issue with the rad .....what do you think?

[LeeRoy]

You either need a higher rated switch or a lower rated thermostat.

I'd be more inclined to get a cooler thermostat.

[Smokey228]

Personally I would not bridge a second fan off the same relays. Even though the relays are rated at 20 or 30 Amps, the spade pins are only rated around 15A, and a single relay and base will melt over time with two fans (had it happen). For peace of mind, a single fan per circuit :)

And yes, when you turn the ignition off, the relay solenoid is de-energised and the relay contact opens.

So in total i'll need 4 relays?? 2 for each fan??

Cheers,
Jase

[The Witzl]

Hey - i made a booboo... and it took 3 years for people to work it out!!

LOL t o y m o d s !

[Mos]

So in total i'll need 4 relays?? 2 for each fan??
If you want to wire it up like this and be sure it won't melt, yes :) Or use high current relays - ie with 9.5mm spade connectors.
You could chance it - I did, once, and never will again (with two fans drawing under 7A each (measured) with 30A relays). I do, however, tend to hook them up with NO thermostats to reduce the number of relays.
Toyota uses 30A circuits and 8.5mm connectors for fans and they would have done sufficient R&D to determine that this was the most optimal solution.

Hey - i made a booboo... and it took 3 years for people to work it out!!
LOL t o y m o d s !
So is that saying that no one has used the information ;) It "looked" right, I just never had a good look for the pin number on the relays :p

Mos.

[Cuzzo]

Hey - i made a booboo... and it took 3 years for people to work it out!!

LOL t o y m o d s !


can someone explain the failz to me. ive used the diagram straight up and it works fine.

[Mos]

It required the relay to make a connection between 87 and 87A which means it will do nothing. If you substitute a relay with two 87pins, then it just shorts and runs the fan full time.

[SillyCarS]

ok so im wiring my microtech to twin thermos in a 23 celica. just posting here so folks can see how im doing it with the single output from the comp

i bought 2 supercheap 12" thermos. the brand is calibre and they go for about $60 each.

http://i57.photobucket.com/albums/g222/craigafleming/15042009782.jpg

the relays that are supplied are 40A so im happy to just run the signal from the microtech in parrallel to each relay for switching (for the n00bs this means the power remains the same for the signal wrather than being split in two when you wire in series, which will halve the 6v power (which is what i think microtech runs at) output to 3v which is hardly sufficient (i think)) the other black box jigga that you can is a 15A fuse, which is also supplied

http://i57.photobucket.com/albums/g222/craigafleming/15042009786.jpg

the fans are to be mounted on a hyundai excel radiator which looks like this

http://i57.photobucket.com/albums/g222/craigafleming/15042009784.jpg

so mounting the fans is the biggest pain in the arse you're gunna have to deal with. first off you get given a whole bunch of shit, nfi how your supposed to use it. and ofcourse the fins will never line up the way you would like them to

http://i57.photobucket.com/albums/g222/craigafleming/15042009790.jpg

or you could just line it up and drill through the fan housing itself. much easier.

http://i57.photobucket.com/albums/g222/craigafleming/15042009789.jpg

then put you bolts in and gently tap them. this will show you where to pry apart the radiator fins for you bolts. i drilled mine. i found it doesn't acutally remove any material, it separates in nicely though

http://i57.photobucket.com/albums/g222/craigafleming/15042009788.jpg

http://i57.photobucket.com/albums/g222/craigafleming/15042009791.jpg

finished

http://i57.photobucket.com/albums/g222/craigafleming/15042009792.jpg

EDIT: this will be edited as i go

[sillycar chick]

Hi Guys,
I have wired up my thermofan according to Witzls diagram, but I used the diagram I had saved to my computer pre-Mos' changes, where the thermofan +ve was coming off pin 30 in the old diagram compared to pin 87a in the updated diagram. Wiring it up this way makes my fan run constantly, does this sound right? Henc why the diagram was updated to the correct wiring? I can post up the old diagram if youre unsure what im on about but I dont want to confuse others reading this thread :)
EDIT: I just rewired up to the Mos-modified diagram and the thermofan still runs constantly :( Gerrard got me the switch out of a camry ages back at the wreckers, whats the chances its dead? I heard they were pretty reliable :-S

Also, does anyone know what temp the Toyota switch in the first post comes on/off at?

And is there any reason why I cant use both relays as 5 pin relays, and just leave the 87a disconnect on the first relay as per the first diagram in the first post?

Thanks for your help guys :)

[RA35GT]

Heya Silly,

Disconnect the thermo switch wire from the thermo switch. The fan should then turn on.

Then connect the thermo switch wire to ground, then the fan should turn off.

If this isn't the case then there is a wiring issue with the relays.

If it tests out ok, then your thermo switch may be the wrong type or is faulty.
To test the thermo switch pull it out and test for continuity between the body and the connector. It needs to be short circuit below the trip temperature and then open circuit above the trip temperature. (Test in a saucepan on the stove with a thermometer).

If your thermo switch doesnt operate as above, but instead is open circuit below the trip temp and short circuit above the trip point, then you have to slightly change the wiring. You just have to connect the fan + to pin 87 instead of 87a. (PS. In this configuration if the thermo switch wiring becomes detached the fan will NOT turn on. Also if the switch craps out you need to add an alternative way to turn the fan on. i.e. carry a wire link or similar)

[sillycar chick]

Hey,
The fan stays running regardless of whether I disconnect the wire going to the thermo switch or not. Its wired up as per witzl's diagram on page one and im using the same sensor he has used in that example, off a camry. It looks exactly the same as in the photo in the first post. :confused:
I wont have a chance again to test the sensor until the weekend...
Thanks for your help!
Dana

[takai]

Remember that some sensors are normally open, while others are normally closed, and they can look visually identical

[RA35GT]

Silly, does the fans turn off if you connect the thermo switch wire to ground?

As takai said, you may have a different sort of thermo switch.

[sillycar chick]

Ok, i'll check that tonight and see if its the case....

[PlacentaJuan]

i am hooking up a thermo switch (normally open 95degrees on, 90 off) and want to know how to wire it up so that the a/c will turn on the fans if the temp is <95 but it wants the fans on.

i cant work it out.

i allready have 2 thermo fans running through 2 relays, do i put the thermo switch to switch 12v or ground? how do i wire in the a/c without the thermoswitch turning on the aircon?

[RA35GT]

y0 PJ.

What you need to do is to to add another relay so the a/c and fans are isolated. (Also means you can trigger using +12V of the A/C compressor). Diagram attached dood.

PS. If you want to turn the fans on using the HP switch the wiring is a little different because the HP switch is a switched ground. (Take Pin 86 on the extra relay off pin 30 and then it needs to go to +12V and then pin 85 of the extra relay will go to the HP switch)

[PlacentaJuan]

thanks for that ^

can you do the digram with the relay symbols (insteal of just the pinouts) because i can understand it much better.

i want to wire it up to the HP SWITCH< THAT WAS I WONT have the fans running on the highway if the a/c doesnt require them.

i will do what mos suggested in an earlier post, and wire the thermo switch to switch GROUND and run it in paralell with the HP switch.

[RA35GT]

hey dood, not quite sure what you mean by relay symbols but I assume you mean show the contacts and the coil. If so, this is attached.

I am pretty sure the HP switch is a normally open switch (it is in a mkiii) but you need to confirm that on your car. (If its a normally closed switch will need to change the wiring slightly and use a different relay)

[CrUZida]

Rudi, pretty sure the mkiii is wired up with the HP switch and the TFS in parallel - ie without that 3rd relay.

I also used a single 40A relay to activate both fans.

[RA35GT]

y0 Andrew,

Yeah, your right.

If you connect to the HP switch you don't need the 3rd relay because its already isolated.

I shoulda thought of that LOL.

Thanks, will change drawing.

--EDIT--
Actually, if the thermo switch turns the fan on then the AC condensor fans would also come on if fitted even if the AC isn't on. (Going by MKIII diagrams). No biggie though IMO.

[CrUZida]

Actually, if the thermo switch turns the fan on then the AC condensor fans would also come on if fitted even if the AC isn't on. (Going by MKIII diagrams). No biggie though IMO.
Surely though if you are running twin thermo's (such as AU) then you'd remove all the stock condensor fans as they'd become redundant.

[RA35GT]

Well, I would think so, but you never know.

[CrUZida]

Haha, indeed you don't!

[Cressid@]

hi, I am in the process of wiring up ford AU thermo fans on my cressida.
I have aircon working. If you could kinda draw a diagram to help me wire it up thanks?
I was going to copy the above diagrams. But I have 3 of them from previous pages and I dont know which one is correct to use for my application.

edited: what is HP switch?
I have got a temp switch Normally Open/

cheers

[RA35GT]

If you have a Normally open temp switch than any of the diagrams I posted up within the last few days, should work for you. (Latest diagram 101_7330r.jpg)

The only difference is how its wired into the ac system. (PS the HP switch is part of the AC system. its used to turn the condensor fans on factory systems when the a/c was becoming less efficient). You do not need to wire the HP as its not essential, but it would make the a/c work better in some cases.

[CrUZida]

HP switch is High Pressure switch (part of the aircon circuit)

Use the last diagram.

[Cressid@]

OH! Understood thanks.

[PlacentaJuan]

finished the wiring last night, and it works perfectly.

the hardest part was finding (and identifieing) the A/C LP switch. (which is just behind the RHS front strut tower down near the crossmember on mx83)

there is zero visibility on me mx83 and had to do it by feel, and its right next to the DUAL PRESSURE switch also.

after a few hours of mucking around i foudn that to confirm you have the right switch, when the DUAL PRESSURE switch is unplugged, the a/c magnetic clutch will NOT turn on (you can hear it quite clearly with the engine off and key in ACC mode)

the HP switch is only responsible for turning fans on/off, so if you have removed all your fans during the engine converion (like i did) then it wont do anything, and unplugging it then turning the a/c will have no effect on the mag clutch.

once i foudn the right switch i traced the wires back to behind the washer fluid bottle (for easy access) and spliced in a wire to hok it up in parallel with the THERMO SWITCH, and both of them switch to ground.

so now i dont have my twin fans running full time (it only takes 30second to cool the engine down to <90 at idle so it was a major waste of power and fan life) and the aircon has acess to the fans when required also.

btw now i notice how loud the fuel pump is!
thanks guuys for your help.

[takai]

Oh yeah, just FYI.
I know that Cruz has got away with running a pair of fans off a 40A relay, but if you are going to run the AU falchoon fans, then definately use two 30A relays.
Ive monitored a constant 21A draw from the fans, which is pretty damn excessive, but they do shift a lot of air.
I initially had mine running off a single 40A relay, which fried quite nicely. Now runs off 2x30A relays.

Also highly recommended is having neat wiring and relay locations like this:
http://gallery2.plebeians.net/d/29224-1/IMG_0868_s.jpg
Makes a world of difference when you are trying to find a fault.

[CrUZida]

Fair enough Takai, I was told they pulled 15A each, which is why I went for the 40A relay.

[The Witzl]

i would be using fully insulated female spades on your fused distribution block there chris.
You know you are going to short them out one day soon!

Re. using a 40A relay - if the relay still uses 1/4" spade terminals, then its realistically limited to 20A current anyway - above that and the temp rise at the terminal becomes quite high and you get excessive terminal resistance.
Also - remember that electric motors can draw SEVERAL times their normal current draw on startup and when under load. So i fyou were close to a relay's current limit, this would burn it out pretty quickly.

[CrUZida]

It was a Jaycar relay and harness...

[takai]

i would be using fully insulated female spades on your fused distribution block there chris.
You know you are going to short them out one day soon!

Re. using a 40A relay - if the relay still uses 1/4" spade terminals, then its realistically limited to 20A current anyway - above that and the temp rise at the terminal becomes quite high and you get excessive terminal resistance.
Also - remember that electric motors can draw SEVERAL times their normal current draw on startup and when under load. So i fyou were close to a relay's current limit, this would burn it out pretty quickly.

They have heatshrink over them now. That photo was taken quite early on.

[The Witzl]

It was a Jaycar relay and harness...

those are 30A continuous rated, and 40A burst.
just buy another one :)

[CrUZida]

Not my car anymore :)

[RA35GT]

LOL.

Will fix :)

[CrUZida]

Its been running for almost a year, including lots of hot summer days where it would have gotten a serious workout.
I'd be happy leaving it if it was still my car (would probably be worth buying a spare incase it stuck shut)

[RA35GT]

Yeah I'll just do that, get a spare and fix it when/if it breaks.

[CrUZida]

wrong wedding...

[Herus]

Dont worry, I just read what was written on page 4, which I had done a good job of missing so far.

Thanks guys,

Herus

[Cressid@]

+ reps for you all!

but i dont think you guys care. :D

wired all up and it works first go.

Now I dont have to top up water every times it cools down anymore! yay

[Cuzzo]

Hi,

Thread Dig,

Im going to wire two EL thermo fans using this diagram
http://www.toymods.net/mos/img/fans/Fan%20Wiring%20NC.JPG

But how will i wire the second fan without drawing excessive amperage through either of these two relays. ( i plan on using two relays only)
edit: Also the thermo switch i have is NC

[CrUZida]

To answer your question, you can't the way you've wired it up.

That first relay is pointless.

[Cuzzo]

Well i havent wired it that way currently.

Can you suggest or point to a diagram on how i should wire two thermos?

Use the second relay diagram twice?

[CrUZida]

Use the 2nd diagram twice.

The first relay there has no benefit, just do the 30 and 85 connections straight to two '87A enabled' relays directly.

[CrUZida]

Actually, I can see why you've done it that way.

Ditch the NC sensor and get a NO.

[Cuzzo]

OK i think i understand.....

Like this?

http://img121.imageshack.us/img121/185/fanwiringncnew.jpg

[Cuzzo]

Actually, I can see why you've done it that way.

Ditch the NC sensor and get a NO.

I dont really want to ditch the NC sensor.(just got it today at $50 :( )

[CrUZida]

If you want to keep the NC switch, then you'll need to wire that first relay in, otherwise your thermo's will run when you turn the key off, or run 3 relays.

You can get a 40A relay to replace the 2nd relay (and consequently the 3rd), but some don't recommend it.

[87lux]

edit i stuff up

[Cuzzo]

So umm i dont wanna use three relays cause that would be gay.

Can i get two relays in one thats weather proof?

[Sciflyer]

Hi

chaserbuddy.

You can always do what I used to do and use one of these to drive you thermo fan relay:
http://www.altronics.com.au/index.asp?area=item&id=S5595

I used to just bolt em on to the thermostat housing with an ally tab.
Good for a quick & cheep solution :D
Just make sure to get the 'Normally Open' type.

-A

I tried these and they work better than i thought they would (so far)

I used a N/O 80deg as above and just stuck it to the top of the radiator with a mix of superglue and heatsink compound

Setup is a 78deg thermostat, JAR alloy radiator and AU Falcon twin thermo fans

http://dl.dropbox.com/u/542878/thermbreaker.jpg

At the moment the fans are just wired in series (ie, half speed) through a single 30A relay and this seems to be fine for normal driving - they only come on if idling for a period of time (ie long set of traffic lights) and surprisingly the hysteresis isnt too great - on switch off the fans will run for maybe a minute or two which is good.

Will try wiring in an additional thermal breaker of a higher temp and relay which will switch the fans to full speed

+rep for this thread!