Wiring up SpotLights and Fog Lights to AE102 Corolla

[bansheebuzz]

MOS - BTDT? whats that mean?

Birdie, Dont go off that relay page, the concept is there but it wont really help, i will scetch you a diagram to help you an send it to you.

o man - You should give up mate, you have guided birdie incorrectly how to wire up his spot lights. Relay for spot lights under the dash sounds like a home job not an auto elec job. No one with a good electrical knowledge would do that

[Mos]

MOS - BTDT? whats that mean?

Been there done that

o man - You should give up mate, you have guided birdie incorrectly how to wire up his spot lights. Relay for spot lights under the dash sounds like a home job not an auto elec job. No one with a good electrical knowledge would do that

Oh cmon, lets be nice to each other We're all here to play toyotas.
I believe Owen was commenting on "professional" auto elecs installing hanging relays under the dash - not necessarily for spotlights. While I'm sure it's not a reflection or comment at all on your business, one cannot ignore that this does indeed happen...

FWIW, toyota foglights are generally powered by a relay in the passenger side kick panel - not ideal, but that's how they do it (don't ask me why ).

Mos.

[bansheebuzz]

FWIW, toyota foglights are generally powered by a relay in the passenger side kick panel - not ideal, but that's how they do it (don't ask me why ).

Mos.

for some strange reason the like putting the ac fuse and relay there too

[BrianRA23]

Birdie

As I said in my post there is the possibility to connect to one wire under the dash that will allow you to run your spotlights so they come on only when high beam is on with your spot light switch - with no other problems.

I have done headlight changes on a few of the cars I have had and found out about the above when mounting spotlights on a Surf I once owned. This is the easiest way to do it even though it didn't seem to make sense at the time.

Phone a 4WD shop and ask the installer how they do it.

Ideally the relay should be placed to allow the shortest distance between battery and the lights themselves to prevent voltage drop.

[Mos]

for some strange reason the like putting the ac fuse and relay there [passenger side kick panel] too

Well, that's not necessarily strange IMHO. A/C fuse usually runs off the blower relay, which is usually located in the passenger side kick panel because it's close to the blower itself. The current for the blower is a great deal higher than for A/C, so the location of the A/C components is not that critical. The MX83 (strangely) runs four wires under the P/S guard to the (independent) A/C relay in the fusebox, with connections only in the cabin.

The factory log light relays run a power feed sometimes from the engine bay fuse box (less strange), and sometimes through the driver's side kick panel fusebox and its 3 metres of wiring (more strange). The power from the relay then goes out from the cabin to the front (completing the strangeness).

Some cars have the blower relay in the engine bay fuse box, which gives more flexibity to the location of A/C components if you want to keep cabling shorter, but the foglight wiring makes no sense at all.

Mos.

[Mos]

As I said in my post there is the possibility to connect to one wire under the dash that will allow you to run your spotlights so they come on only when high beam is on with your spot light switch - with no other problems.

I have done headlight changes on a few of the cars I have had and found out about the above when mounting spotlights on a Surf I once owned. This is the easiest way to do it even though it didn't seem to make sense at the time.

Brian, could you please elaborate on which wire this is?

Mos.

[bansheebuzz]

birdie sorry i could not sent the pic

The easy way to wire spot lights is run a piece of twin from headlight connector, past the spot light relay to a switch inside.

At the headlight connector join each wire to the outer wires on the headlight connector

run past the relay, cut one of the wires in your twin and join the wire to pin 86, and 85 on the relay

run it inside and join the cable to the switch,




This is basically how it will work
headlight connector Relay
Headlight + >----------------------------86<><>85------------------------------------------\ switch
High beam - >-------------------------------------------------------------------------------------/

[BrianRA23]

Mos

I would like to tell you exactly which wire it is because I know it works, but I work offshore and I am currently in Africa. To confirm the correct colour I would phone ARB and ask to speak to the installer. However, I was thinking about this last night and the only wire I think it could be is the one that is used for the high beam indicator light on the dash, which is the same as the low beam light wire from the headlamp.

I know that the HB indicator light is wired in parallel with the low beam switch on the steering column and the light goes out when on low beam because there is not enough to make the HB indicator bulb glow. When on low beam power still runs through the the low beam lamp up front but since the bulb on the dash is has a high resistance you cannot notice it at your headlights.

I suspect the current required to activate a relay (for spotlights) is still low enough to not cause the low beam lights to not come on.

So to connect it up just tap into the above mentioned wire, run it through a switch to be mounted on the dash and run the wire forward to where the relay will be mounted. Connect the other side of activating circuit to earth and the relay should work correctly.

All that is left is to add a fused power to actually run the spotlights.

The idea suggested by banshee sounds like it would also work, but will result in slightly less voltage available to run high beam ie less light (if noticable). It is also a slightly less conventional configuration.

In addition to all the above comments I would (and have) be put relays on high and low beam to reduce voltage and give better lighting on low beam as well. I have an additional 4 relays on my cruiser just for lighting, and no I don't think this is overdoing it. This compensates for the low gauge wire used in the lighting system and the long route taken where all current must travel through the stork on the column (sometimes burning the contacts over time resulting in less voltage to the lights).

[bansheebuzz]

[QUOTE=BrianRA23]Mos
The idea suggested by banshee sounds like it would also work, but will result in slightly less voltage available to run high beam ie less light (if noticable). It is also a slightly less conventional configuration.
QUOTE]

?? less voltage this is just the trigger side of the relay, 86 and 85 are the trigger pins
you then have fused battery supply to pin 30 and then 87 to spots.

As far as less conventional, it works perfectly fine, and it is quick and efficiant to do it this way

[Mos]

I was thinking about this last night and the only wire I think it could be is the one that is used for the high beam indicator light on the dash, which is the same as the low beam light wire from the headlamp.

Of course! (Doh )

I know that the HB indicator light is wired in parallel with the low beam switch on the steering column and the light goes out when on low beam because there is not enough to make the HB indicator bulb glow.

The HB indicator bulb is shorted out when the stalk is switched to low beam, so yeah, no light.

When on low beam power still runs through the the low beam lamp up front but since the bulb on the dash is has a high resistance you cannot notice it at your headlights.
I suspect the current required to activate a relay (for spotlights) is still low enough to not cause the low beam lights to not come on.

Relay will draw a little less current than the indicator bulb, so it should be Ok. Worst case the low beam will have a faint glow.

The idea suggested by banshee sounds like it would also work, but will result in slightly less voltage available to run high beam ie less light (if noticable). It is also a slightly less conventional configuration.

Not sure if you're picturing it correctly as his idea is fine and it does not affect the voltage available to the hi beams at all. The relay solenoid "pretends" it's a third hi beam filament in parallel with the others, and draws very little current, so will not affect filament voltage.

In addition to all the above comments I would (and have) be put relays on high and low beam to reduce voltage and give better lighting on low beam as well. I have an additional 4 relays on my cruiser just for lighting, and no I don't think this is overdoing it. This compensates for the low gauge wire used in the lighting system and the long route taken where all current must travel through the stork on the column (sometimes burning the contacts over time resulting in less voltage to the lights).

Yeah, the whole happy laps of grounding cables and stalk switch are one of those accountant's decision that seem to annoy engineers.

Mos.

[BrianRA23]

Mos - I am glad the idea makes sense to someone else

I did get what was suggested by Bansheebuzz, but I guess I might be being picky by saying there will be slightly less voltage. I was thinking 2 x 60W = 120W and a relay might use 2 - 5W to activate so this will result in a possible 1-4% drop in voltage.

Consider people change who their bulbs to go from 60W to 100W on high beam and only get a 15% improvement in light (or so I have read) with the rest going in heat. I have done this and noticed huge improvements so maybe the 1-4% might have an affect.

I have since decided to stay with the standard wattage, but using the newer high output versions and then fit relays as mentioned. I am happy with the results and don't have to be scared about burning the lenses and reflectors in my headlights.

[bansheebuzz]

the way some 4wd shops do it is run a wire from the lb, through pins 86/85 on the relay, to the switch inside to earth under the dash.

The way it works is battery supply runs through the lb filament(while on hb), throught the relay triggering it to ground via the switch

[bansheebuzz]

but seing you still need to connect up outside under the bonnet to the headlight connector, i find it easier to make the connections the in the one play(at the back of the headlight connector.

You could join onto the lb wire under the dash, through switch out to relay to earth under the bonnet but it is easier to find the wire at the headlight connector

[Mos]

Mos - I am glad the idea makes sense to someone else

I did get what was suggested by Bansheebuzz, but I guess I might be being picky by saying there will be slightly less voltage. I was thinking 2 x 60W = 120W and a relay might use 2 - 5W to activate so this will result in a possible 1-4% drop in voltage.

I think you're thinking that the light supply is only capable of supplying a certain wattage and the relay will pull some of that wattage. The wattage capability is limited by the resistance of the cabling from the alternator, through the relay to the filmament positive. The current draw from the relay will be miniscule, so the source resistance of this filament power supply should not cause any significant voltage drop.

Working with 12V, with a 60W globe the wiring is supplying 60W / 12V = 5A per filament, or 10A per system. Our automotive relay typically draw about 100mA, or 1/100th of the filament current, for the solenoid.
To reduce the voltage by 1% (0.12V) the source resistance (resistance of all of the circuit from the 12V all the way to the relay solenoid) would need to be 0.12V / 0.1A = 1.2 Ohms.
Now if we use this source resistance to calculate the voltage drop due to the current from the bulb filaments, we would get 1.2 Ohms * 10A = 12V (because the 10A current must also flow through this source resistance in order for the relay current to cause a voltage drop). A 12V drop obviously will result in no voltage supply at all to the filaments, the source resistance can't be anywhere near 1.2 Ohms.

If we calculate with something a little more realistic, like say a 1V drop due to the 10A filament current, we get a source resistance of 1V / 10A = 0.1 Ohm. Taking the relay solenoid current at 100mA, we get 0.1A * 0.1R = 0.01V - resulting in a very small percentage drop.

Not having measured it I have no idea what the actual voltage drop to the filaments is, but I'd suspect it to be a lot less than 1V. In any case, the relay solenoid current will not create any voltage drop of interest to the filament supply.

Consider people change who their bulbs to go from 60W to 100W on high beam and only get a 15% improvement in light (or so I have read) with the rest going in heat. I have done this and noticed huge improvements so maybe the 1-4% might have an affect.

I have since decided to stay with the standard wattage, but using the newer high output versions and then fit relays as mentioned. I am happy with the results and don't have to be scared about burning the lenses and reflectors in my headlights.

When you switch to higher wattage bulbs you are creating a higher voltage drop across the wiring, with a certain source resistance, resulting in a lower supply voltage at the filaments. Upgrading the wiring with individual relays and thicker and shorter cabling decreases the source resistance of the supply, resulting in more actual voltage being available at the filaments.

As implied in previous posts, upgrading the wiring while still using factory wattage bulbs should result in a noticable increase in brightness due to the removal of the massive amount of superflous factory cable length.

Mos.

[o_man_ra23]

By running the wiring straight through the contacts in a relay, the coil resistance will be in parallel, and so the coil should have almost zero resistance on the contact, unless there is a fault. 1sqmm cable has a nominal reistance of 21 ohms per km. so over 3 metres (lets be generous) there will be a cable resistance of 0.06ohm. at 12V and 5A (running lights parallel, the currents dont get added, and the source voltage is identical) we then have a voltage drop of 0.3V which is 2.5%. But dont forget the alternator charges at 14.4V, so the voltage drop is in fact 2%, and the voltage at the light will be 14.1V. All other currents are in parallel, and will not cause voltage drop across this circuit.

But, as the voltage increases, so does the current, and as the voltage drops, so does the current. Lights work on current to heat the filament, not voltage. The voltage is only there to provide the current. So, if the light is rated at 60W for 12V, then the filament has 2.4 ohm resistance. At 14.1V, this will then have a current running through of 5.9A, and a total power consumption of 83W. This will in turn cause a greater voltage drop on the cable, a lower current through the filament, and a lower power output.

But still, you will, from a working system, get a better output than the rating.

Cheers, Owen