Pontiac Repair: AC blowing hot, pressure 80lbs, pontiac montana, electrical fault

Question
Our 2002 Pontiac Montana's AC is blowing hot. I bought a charger with a gauge and the pressure is approx 80lbs. What would cause this high pressure, what might it cost to fix?

Answer
Hi greg:

the pressure yourreading is more than liley the ambient temp under the hood. If the compressor is not running the pressure in the system will be that of the underhood tempature. does the compressor run when you turn on the a/c? If the compressor is not running and the pressure in the system is 80 psi then there is an electrical fault somewhere in the system. It could be the control head,the engine control computer a relay or the compressor it's self.. It's hard to say what the issue is here with out seeing the car. The aid of a scan tool for the engine computer would help out. That way you can see what the computer is seeing and doing. If it doens't see the proper PSI in the system,or it doesn't see the request to turn on the copmpressor it will not turn it on. Good luck :)