2005 Pontiac Sunfire is overheating. The car has one fan for A/C and coolant...GM. The fan won't turn on by itself so you must run A/C to kick the fan on, keeping the car cool aside from long traffic stops. The A/C then gets warm and car starts to overheat.

What I've "figured out" so far:
The coolant temp switch does nothing other than operate the gauge so i believe, grounded out and gauge pegged and no fan either.It had a bad fan relay which I replaced but fan still wont come on. Fan relay is simple 4 pin, of which two pins have power. My guess is the computer is supposed to ground the the other side of the electromagnet, thus connecting the circuit to bring power to the fan. This is not happening. I can't find any wiring diagrams online and it doesn't seem like there are any other coolant sensors. My next step as far as I see it, new ECU. ANY help is greatly appreciated.

 

I would hard-wire the fan personally.

I did not know they made a 2005 Sunfire. Didnt that thing die in like 99 with the advent of the Cobalt?

 

Lol I opened this thread just to say the same thing....an '05 Sunfire?

 

Fiance's sister's car...I kind of have to fix it. Because the guy she's dating is a ******* tard. So you know...to keep getting ***, do the work, keep her happy.

 

this is how i read you post! my jaw dropped for a second then i re-read it...