[CamaroChriSS]

My AC started blowing warm at idle and is fine while driving. I thought I had a compressor problem, but then when I was driving into DC the other day and hit some traffic I noticed it started running hot - and touched 230-240 before I could safely pull over. Let it cool down for an hour and it’s been fine since (haven’t driven in traffic since), never going above 180, but I also haven’t noticed the fan kick on at any point since then.

1) Is the AC issue related? Does it rely on the fan at idle?
2) has anyone replaced their cooling fan yet? Any write-ups or videos would be greatly appreciated! (Bonus points for part number and link!)

[CamaroChriSS]

And what are the odds of something simpler, like maybe just a bad relay for the fan?

[easttxss]

I don't think our fans are controlled by a relay, they are more complicated than that. I believe they are pulse width modulated by the ECM or Body controller to control the speed. And yes, the A/C needs the fan, when not moving, to function. I would scan the computer and see if there are any codes (some codes don't trigger the check engine light).

[dpevans]

I believe there is a fan control module that is fed by the ECM and the ECM uses a signal from the temp sensor. I would take it to a mechanic and find the what part of the system has gone haywire.

[Gunkk]

If there are DTCs, diagnosis may be easier. OP, check your PMs. Answers to your questions and more can be found therein.

Fan power/control schematic:

[ctrlz]

fan itself or fan control module probably bad.
A/C definitely needs fan blown condenser at idle. Typically fans are on high when A/C is on. May be a bit more sophisticated on our car.

[CamaroChriSS]

I appreciate the input, everyone! I didn’t realize how sophisticated our fans were. Unfortunately sophisticated means more complicated to fix… But this is all very good information!

[KirkH]

Could this be a bad thermostat causing these problems? A bad thermostat caused my AC to blow warm and the cooling fan kept blowing like a jet engine after turning off the car.

[ember1205]

Have you checked the connectors on the fan itself? Granted, it was a long time ago and the car was far less sophisticated... but... I had a car overheat on me driving it in local traffic (which mostly meant stopping at red lights periodically and otherwise driving 30-40MPH. I puled the electrical contact off of the fan assembly, cleaned it, and plugged it back in. Never had another issue.

Always start with the simple things...

[ctrlz]

Originally Posted by KirkH

Could this be a bad thermostat causing these problems? A bad thermostat caused my AC to blow warm and the cooling fan kept blowing like a jet engine after turning off the car.

I believe this has been reported before.
kirk, did the dash gauges give you a bad (or no) temperature reading when the stat went bad?
I must say, though, I remember battery drain from fan running being the main issue before. Fan blowing usually helps the A/C, not hurt it.

[CamaroChriSS]

Originally Posted by ember1205

Have you checked the connectors on the fan itself? Granted, it was a long time ago and the car was far less sophisticated... but... I had a car overheat on me driving it in local traffic (which mostly meant stopping at red lights periodically and otherwise driving 30-40MPH. I puled the electrical contact off of the fan assembly, cleaned it, and plugged it back in. Never had another issue.

Always start with the simple things...

Great point - definitely would prefer to plug in a wire rather than spend $350 on a fan... I'll play around with that.

Originally Posted by KirkH

Could this be a bad thermostat causing these problems? A bad thermostat caused my AC to blow warm and the cooling fan kept blowing like a jet engine after turning off the car.

My first thought when I saw the temp rise was a bad thermostat, but when I parked I realized the fan wasn't running. That, paired with the fact that it runs fine as long as I'm moving is making me think fan.

[ctrlz]

Originally Posted by CamaroChriSS

My first thought when I saw the temp rise was a bad thermostat, but when I parked I realized the fan wasn't running. That, paired with the fact that it runs fine as long as I'm moving is making me think fan.

Agreed.
Weird that this car doesn't throw a code when fan not working.
Maybe fan control module reports OK to the ECM, but fan itself not spinning. So, as long as the module is "commanding" the fan as expected, no DTC?

[LiqTenExp]

There is commanded and actual fan speed reported. I would look at HP Tuners log (or anything than can log this data) to see if the ECU is commanding fans. If it is you at least know there should be voltage applied to them and work your way back. They are PWM fans so you will have more than just 2 wires.