AC not working...

[JML97-3.8]

My ac has been blowing hot for about a year now, when I took it to my mechanic he said it was my pcm and it was not sending the signal to the compressor to turn it on so he told me to replace it, well I bought a pcm (used) and put it in and it still blows hot, or the same temp as the outside air.

Any help?

[chas]

the wiring diagram i have isnt clear about the connection from the pcm to the compressor. i would imagine the pcm drives a relay which activates the clutch on the compressor. pretty sure its was that way on the 3.4 motors.

check the fuse box under the hood for something labeled a/c relay. swap with another relay (assuming there is one) and see if your problem moves.

if the pcm isnt sending a signal to the relay it has a reason. could be the low pressure switch sending a false reading to the pcm.

if the above doesnt help, you might need to find a better wiring diagram (the dealership would probably be helpful about that bit) and track down the signals into the pcm (a/c request and low pressure) out from the pcm (compressor relay to clutch).

[chas]

found the diagram i was looking for (yes, this ended in a preposition -- sue me). in the underhood electrical center there should be a fuse #12 (should be 15A). this provides power to the a/c compressor relay (also in the electrical center i believe) and cruise control. check the fuse. swap relay with nearby relay (i think the starter relay is the same type).

[AllTheGoodNamesAreGone]

if your ac system is low on refridgerent, it will not turn the system on.. thus blowing hot air all the time..

~Billy