a little problem :)

[nghie]

hello there guys. First off, I'll start with the problem.. The thermo fan won't kick in when the engine reaches temperature. So I've hard wired it to ignition. My previous car was a gti swift. It was very primal and the electronics were basic.. So i wouldn't say i was very savvy with electrical systems in cars. Can somebody please post up a guide in lamens terms on what to check.. Where exactly to check, and what parts to replace if need be. So far, my research has pointed me in the direction of the fan relay, and thermo sensor. What and where are these? Thanks guys! Dan.

[Morton]

There is a sensor behind your alternator. It has a blue plug, and two pins. It is screwed into the intake manifold, and sits next to another sensor.

This blue two-pin sensor is your Coolant Temp Sensor, which relays voltage to the ECU depending on the temp of water, and then the ECU decides when to turn on your fan using that information.

The fan relay would literally be a square four-pin relay, in your relay/fuse box in the engine bay. SHOULD be labelled.

[ice_cold17]

that fuse box is on the left side of the engine right above the battery,its usually covered by a black plastic cover,inside the cover will tell you which relay is which,just a matter of changing it with the correct one,make sure you get one suggested by manufacturer as the wrong one could throw the whole thing into the fritz,this happened with mine,my fan turned on but at the wrong times,it got way too hot b4 turning on,all because the previous owner decided to do all the work himself without checking anything,so make sure you get the right relay,sorry to drag on a bit there but its a pain in the ass if you screw it up,believe me good luck with it

[nghie]

So basically, If I changed these two items (Which I will do even if they aren't broken just to be safe); and it still doesn't work, you'd narrow it down to something wrong with the ECU?

Thanks for the tips though, very precise

Dan.

[Andrew426]

I would be looking at your fan if these two things dont solve the problem. ECUs are pretty bullitproof items, they are not known for failing. Also, it would be pretty unlikely for only one output of it to fail.

[ice_cold17]

so the fan does turn on when wired to ignition? if so then the motor on the fan is fine,its just ur fuses or relays,if its not them then you probably have a short somewhere,also change your thermostat,it may not be opening at the right time therefor your fan may not be going because of that,it could also be a short somewhere in the circuit but that would be unlikely in this case,i wouldnt say its the ECU,if it is then you would have bigger probs than just a fan.