ac clutch just stopped engaging / no ac ?

[astrander]

checked all of the relays and fuses under the hood, clutch will not kick with air on, or defrost on?

[gmtech1]

What are the a/c pressures? If the pressure is low because of a leak, the a/c will not engage. If the pressures are ok, then you could have a pressure switch, wiring, HVAC module or a compressor problem. Should have the pressures checked first.

[Tech II]

Like GMtech1 said, you need to get a set of gages on this....normal pressure with engine off, and cold, should be close to ambient air....i.e., if temp is 80F, pressure should be around 80psi on both sides....if below 50psi, you have a leak(if ambient air is 80F)...

If pressure is ok, about the only thing you can do is attach a test light to the clutch harness, start the car and turn a/c on......if it lights, bad clutch...if it doesn't, just double check the ground side of the harness....

Also need to check the A/C clutch relay and it's circuits.....

This has a 3 wire pressure sensor that can't be jumped......so if pressures are ok, then you need a scan tool to read the data from the pressure sensor...it should equal the gages....if the reading is too high or too low, either bad sensor or wiring from the sensor.......if the reading is too high or low, the PCM will not ground the A/C clutch relay....