2003 A/C problem

[metalwarrior]

Pressure in the system is 100psi, the compressor seems to not kick on. is there a sensor or relay i should check?

[szpalko]

I had tons of trouble with ac, FINALLY fixed it.
Be sure you have the pressure. I have about 7 atm or bar(calculate psi) 7-8 bar should be good. Then chek if the button works and you have the light on. If that is good, then check the fuses, all of them, pull them all out and put them back in, its good for the contacts to clean up. If they are good chek the AC relay under the hood. You can measure it out with a multimeter. Find the little diagram on the relay and see which poles need to be shorted if the relay pulls in. You can take out the relay and short the the two poles in the socket with a paperclip. Have the engine running for this and dont short the inappropriate sockets and be CAREFULL, as soon as the AC goes on, so will the big ventillator behind the radiator. If it turnes on with that, the relay was bad. If not, check the plug supplying power to the AC compressor`s clutch solenoid. It is the only plug going into the compressor. Check with a lightbulb or multimeter if it gets power through the AC relay (or paper clip). If it does not, bad wires, if yes, bad compressor or clean the socket and try again. Shorting the relay poles will give you definate answer if the compressor is good or broke. If it turnes on like this, then check the sensor on the high pressure side somewhere near the radiator on the pipeing. My sensor was good, never cared how to measure it. Shorting only two of the 3 poles in the sensor plug should simulate good pressure, dont know which two.
Good luck hunting for the fault!