I would say you need a scan reader that will tell you whether or not the temp sensor is sending the correct temp to the pcm/bcm. If that is correct, and the pcm/bcm is good, I suspect your ac control unit (dash unit) to be defective unless there is a bulletin of other problems.

 

MrCritical, your telling me i should go to my GM dealership and have them put it on there scan machine? The A/C unit you are talking about in the dash. Are you referring to the controls that you turn on and off for the HVAC?

 

The PCM commands Low Speed Fans on under the following conditions:

• Engine coolant temperature exceeds approximately 106°C (223°F).

• A/C refrigerant pressure exceeds 1310 kpa (190 psi).

• After the vehicle is shut off if the engine coolant temperature at key-off is greater than 140°C (284°F) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes.

The PCM commands High Speed Fans on under the following conditions:

• Engine coolant temperature reaches 110°C (230°F).

• A/C refrigerant pressure exceeds 1655 kpa (240 psi).

• When certain DTCs set.

 

I would like to thank everyone for there help and input. Just an update and to let you all know the problem has been corrected. Both cooling fans came on at 210F. Also, had to have the "drag pin" on the PCM adjusted. Temp guage is now reset and the cooling fans are coming on now when the gauge reaches a tick past the half way mark. Air conditioner compressor is seized and needs replaced and the high pressure line on the power steering pump is sweating where a wear mark occurred on the line due to vibration of the altenator. Other then that I had the cooling system flushed, cleaned the trottle body, changed the oil, and now prepairing to have an emissions test to get the car on the road.

Best Regards
Jeffrey Bishop
2001 Chev Malibu owner

 

I have a 97 lumina sedan w/3100 and im having the same problem; overheating at ilde and fans are not coning on...Help