A/C PROBLEMS. It Just want come On!!

[decaresq45]

I have a 94 Q45 and my a/c compressor will not turn on. I checked therelay. I even switched it out with the cruise control relay. I have constant power , ignition power, but something is not sending a signal to the compressor to turn on when i push the a/c button in the car. I can power up the compressor by jumping it off at the relay, then it blows super cold air. I have good pressure on both the high and low sides. I have a new a/c compressor and dryer. My dash lights on the a/c control are out except the numbers. Those are bright and green, but everything else is functional. I wondering if any of you has anyone had this problem. Please Help ASAP

[qship96]

this is a no brainer,you are in atlanta......go to t3 for proper diagnosis

[Q451990]

Time to download the FSM at http://www.phatg20.net and study all of the conditons that have to be satisfied for the compressor to be on. The signal actually comes from the ECU. From memory, the dual pressure switch on the dryer must be on (pressure not too low or too high), the over heat signal from the compressor can't be melted or open, the sensor on the evaporator can't show that it's frozen... etc.

There are about five different conditions that must be satisfied...

Good luck!

Heath