Jim Grant's Tech Tips
‘92 Pontiac Grand Prix, Cooling Fan Operation
I went out and got a new car. It was a ‘92 Pontiac Grand Prix 3.1 MFI V6. Now the problem is the car overheats and kills the car. It will turn back on, but if you go to put it in gear, it will die. The car doesn’t smoke or give out steam. I put 2 new parts in it, a temperature sensor, and a thermostat and I still cannot get the fans to kick in. I checked all the wires and looked at all the plugs under the hood. What makes the fans kick in? I cannot find that out. If you could help me that would be great!
- Jennifer Beenken
The information you’re providing is a bit of a mixed bag. An engine that is overheating so much that it stalls, if not damaged, soon will be if driven under those conditions. I can’t help wonder if you have 2 different problems that you’re tying together. Because a stalled engine cannot damage itself let’s focus on the overheating and/or cooling fan problem. The cooling fan is computer controlled. The computer will activate or deactivate the cooling fan with information from the coolant temperature sensor, A/C request and vehicle speed. A simple test of cooling fan operation can be done by grounding the B terminal on your vehicle’s diagnostic connector. Grounding this terminal will cause the cooling fan to be activated. If the fan doesn’t turn on then you need to check the fuses in the Right Side Electrical Center that is located under the hood on the right hand side in front of the strut tower. There is a 10 amp fuse marked IGN FUSE. If the fuse is good you don’t have to go too far to find the relay for the cooling fan; it’s in the same electrical center. While you’re in there check the fusible element marked “N”, this is the main power supply for the cooling fan motor. If all checks good and cooling fan is still not working, then you need to go to the connector for the cooling fan to see if electrical power is present and the ground wire is good. If they’re good you likely have a bad cooling fan motor.