My daughter has a 2002 Grand Prix - 3100. The radiator fan doesn't come on normally. The two fans normally would come on around 180 F (82 C). Now, they come on only at about 212 F (100 C). As such, the engine temp goes between 212 F (then fans kick in) and then drops to 180 F (after the fans stop again). Both fans will run when I turn the AC on & with with the interior blower fan on high. Also, both fans will run when I disconnect the ECT (Engine Coolant Temperature) Sensor.
I read somewhere that this means the radiator fan relays and the Engine Coolant Temperature senor are fine (I'm not sure this is accurate). In the end, it seems to me the only causes could be a relay, the ECT sensor or the PCM. Hope it is not the PCM as I understand these are expensive. Any advice would be appreciated including possible fixes to bypass the PCM controls so the fans will run. It appears that we can drive the car - not sure it is good for the engine but seems to be OK as long as the temperature doesn't go higher. Thanks in advance!
