Hello i am trying to see if someone can tell me what the different computers on my 2004 grand prix operate. For instance what the the ECM control? What does the BCM control and What does the PCM control. Having a problem with the cooling fans operating properly. Changed the coolant temperature sensor no air in the system. So the mechanic says it is one of the computers. But not sure which one with our running a diagnostic check on the car.
So i someone can tell be if it is the ECM that controls when the fans turn on when they should or is it one of the other computers? The fan on the drivers side comes on when the ac is turned on but then turns off when the gauge gets to the half way point on the gauge and will not come back on. Right now it is direct wired. Also the ABS lights and the traction control lights have been on the dash for a while and the lights where the ac controls are flash at night when the head lights come on? I know i have a haunted car but i love it still.