Q: What is the proper operation of the compressor clutch and how can it be checked if the air conditioning system is not cooling?
A: First of all, check the A/C Clutch, warm up the engine, and set the AC to the coldest setting with the Cooling Fan Assembly on high. Open the doors to prevent the system from cycling off too quickly and have your assistant push the AC button while you observe the compressor. The clutch should click and rotate but if not, turn off the engine and disconnect the AC system pressure switch and use a paper clip as a jumper and try again. Then if it works, have the system tested by a shop. If the clutch doesn't operate, inspect the fuses and test the compressor clutch relay. Inspect for power at the relay socket and test the large heater relay. While the engine is running and AC is on, attach sockets 3 and 5 of the relay with a jumper wire and listen for a click. If it still doesn't work, remove the clutch connector, and check for continuity between the relay socket and the compressor clutch connector. If there is no continuity, inspect the circuit. If there is continuity, check for an opening in the circuit from the PCM to the relay box.