Cooling fans not working on my Grand Prix GT. replaced all 3 relays & eng coolant temp sensor & added a new thermostat . Any ideas ????


Asked by May 01, 2012 at 04:57 PM about the 2002 Pontiac Grand Prix GT

Question type: Maintenance & Repair

Is there some thing I have missed in my checks???

6 Answers


check all fuses seen this where a fuse marked fore something else actually had power to the secondary panel test every one ok even if you think you already did

6 out of 6 people think this is helpful.

I think there are two temperature sensors, one that reads out in the instrument cluster and a seperate one that controls the radiator fan (s). When you turn on the AC the radiator fan (s) should come on. If not you may have a bad fan motor or the secondary temp sensor I mentioned. Try taking 12 volts from the battery straight to the fan motor, if it doesn't run....the motor is bad. Good luck with it.

10 out of 10 people think this is helpful.

Already checked both fan motors to direct power and they are fine. Have replaced eng coolant sensor & dash meter is working... Have in clipped wiring to temp sensor & made a open loop to engage fans at high, fans will not run with A/C on as well... Power running to wiring harnesses so lost as to what to check next???

10 out of 10 people think this is helpful.

If both temp sensors are known to be good and all of the relays are known to be good you might try jumpering the relay contact sockets (bad connection). If none of these things bring the fan(s) on you may very well have a computer problem. The signal from the fan temp sensor tells the computer to energize the fan relay so once again if the fan temp sensor is good the relays, connections, and motors are good it only leaves the computer. Good luck with it.

4 out of 4 people think this is helpful.
Jason Zane

how hot did it go up to? 220?

5 out of 5 people think this is helpful.

In most cases the power is applied to motors, lights , etc. the control relay is making and breaking the ground. Just thought I'd bring this up to you as you said the harness had power on it, that would be a normal situation any time the battery is connected. Good luck with it.

2 out of 2 people think this is helpful.

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