The clutch at the front of the compressor engages so that the compressor will turn with the fan belt.
Since the clutch is not engaging, the compressor is not turning so the ac system is NOT working. The clutch is energized when the ac is switched on, however there is a low/high pressure switch that is a part of this circuit. If the pressure is low the circuit is not completed so the clutch is not engaged. If the pressure is too high, the circuit is not completed so it will disengage the clutch and prevent the compressor from building the pressure any higher.
Since the clutch is not engaging I would look at the circuit that engages the clutch. Could be that you are low on refrigerant, or that you have a bad relay.
Last edited by upallnight; 01-24-2013 at 06:32 PM.