Thermo fans

**Ghetto-AW11** · 06-08-2006, 10:57 PM

Hey guys,
My thermo fans are constantly running when the iginition is on. The water temp sensor is fine as the temps read perfect on the microtech, but what i believe is wrong is that the microtech is getting the signal from the temp sensor and the stock ecu is still controlling the thermo fans.........

The person who installed this microtech so far has yet to help me out with this and isnt answering his phone. I presume its a matter of connectiong the wire going to the stock ecu to the microtech but alas I have no wiring diagrams.

**feral4mr2** · 06-08-2006, 11:41 PM

the temp sender for the thermo's is a different one to what reads the coolant temp for your guage (and quite possibly where the microtech reads from).
the thermo sender is on the radiator down the right hand side (standing facing the front of the car).

**adamaw11** · 07-08-2006, 08:54 AM

Have you got air conditioning? or just removed it.

After removing a number of air con parts, I found the thermo switch for the air con makes the fans turn on if you unplug it so I just left it plugged in.

**chris davey** · 07-08-2006, 11:48 AM

why not rewire it?

If the MT is receiving the correct water temp sensor then all you need to do is directly wire the thermo from an aux output through a relay. Too easy

**Cuzzo** · 07-08-2006, 07:54 PM

yeah thats what i would be doing. Do you have the microtech wiring diagram?
I have a lt-10s diagram if u need it.

**Ghetto-AW11** · 07-08-2006, 08:26 PM

Nah, i dont have the LT8 diagram either...

Im guessing its pretty simple stuff if you have the right information

**Cuzzo** · 07-08-2006, 08:29 PM

The only problem is you will have to wait til tomorrow, as i dont have it on me now. Ill try and find one off the net.

**Cuzzo** · 07-08-2006, 08:39 PM

OMG Microtech diagrams as far as the eye can see. However i cant see on here where to wire the thermo fan into. And the lt-10 diagram is a mxt-8 diagram(different to mine)

http://www.microtech-efi.com/support/downloads.html

**mullett** · 07-08-2006, 08:45 PM

Mine started to do that a while ago (still running stocko ECU). Dead sensor? I'll run it off the EMS when that's in I guess, for now it's not really a problem short-term...

RM.

**camrygt?** · 07-08-2006, 09:34 PM

My camry fans run if you unplug the fan temp switch. The ecu doesn't have anything to do with them (on my car at least). The switch and relay are wired as a fail safe arangement to turn on the fans if the switch is disconnected.
Might be your problem

Fan output on MT or LT microtech is usually Aux output 1

**Ghetto-AW11** · 08-08-2006, 12:32 AM

ill see if the connection is ok to the temp sensor at the radiator in the mean time before i get it wired to the microgay.

**feral4mr2** · 08-08-2006, 02:07 AM

Originally Posted by camrygt?

My camry fans run if you unplug the fan temp switch. The ecu doesn't have anything to do with them (on my car at least). The switch and relay are wired as a fail safe arangement to turn on the fans if the switch is disconnected.
Might be your problem

indeed, same set-up on the aw11.

grab a multimeter and see if there is earth (12v - neg) on both wires coming from the fan temp sensor doobie on the radiator (unplug it 1st), if it has it's cactus. the thermo fans turn on/off basiacly the same set-up as the eng bay fan with that temp sensor in the eng bay useing a neg trigger.