Expert: Candido Figueroa - 5/12/2010

Question
QUESTION: hi i have an 02 silverado my a/c is not working. i charged the system to about 38 pounds, but my compressor wouldnt kick in. i checked all the fuses and relays, everything checked out. then i jumped the relay with a wire to engage the compressor, but it still wasnt blowing cold. not sure what to do.

ANSWER: Hi Chris

On a 02 Silverado you should have added 38 oz. and you should be above 50psi for the cycling switch to turn on the compressor.  Not sure if you mean 38 pounds or 38psi.

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QUESTION: i meant 38 psi so if i charge it to 50 or above a little it should kick in and work then right?

Answer
When running your system should be at 25 to 45 psi.  It will turn on when you hit 50 psi and will turn off when it drops to 18 psi.  Once it starts it will cycle until you get in the 25 to 45 psi range this is all dependant on ambient temperature.  The otter it is the higher the pressures.  Your high should be between 175 and 225 psi.  Let me know if you need anything.