A/C Compressor Clutch Circuit Troubleshooting (With A/C)
A/C Compressor Clutch Circuit Troubleshooting
NOTE:
- It is normal for the A/C compressor to turn off under certain conditions, such as low idle, high engine coolant temperature, hard acceleration, or high/low refrigerant pressure.
- Do not use this troubleshooting procedure if the fans are also inoperative with the A/C on. Refer to the symptom troubleshooting index.
1. Check the No. 43 (7.5 A) and the No. 10 (7.5 A) fuses in the under-dash fuse/relay box.
Are the fuses OK?
YES - Go to step 2.
NO - Replace the blown fuses, and recheck. If either fuse blown again, check for a short in the No. 43 (7.5 A) or No. 10 (7.5 A) fuse circuits.
2. Connect the HDS to the DLC.
3. Start the engine.
4. Turn on the A/C.
5. Check the A/C CLUTCH in the PGM-FI Data List with the HDS.
Is the A/C CLUTCH on?
YES - Go to step 7.
NO - Go to step 6.
6. Check the engine coolant temperature and idle speed (use the HDS PGM-FI Data List if possible).
Are the coolant temperature and idle speed OK?
YES - Go to A/C pressure switch circuit troubleshooting. A/C Pressure Switch Circuit Troubleshooting (With A/C)
NO - Troubleshoot and repair the cause of the high engine coolant temperature or low idle.
7. Turn the ignition switch to LOCK (0).
8. Remove the A/C compressor clutch relay from the auxiliary under-hood relay box, and test it. Testing and Inspection
Is the relay OK?
YES - Go to step 9.
NO - Replace the A/C compressor clutch relay.
9. Measure the voltage between A/C compressor clutch relay 4P socket terminal No. 1 and body ground.
Is there battery voltage?
YES - Go to step 10.
NO - Repair open in the wire between the No. 43 (7.5 A) fuse in the under-dash fuse/relay box and the A/C compressor clutch relay.
10. Connect A/C compressor clutch relay 4P socket terminals No. 1 and No. 2 with a jumper wire.
Does the A/C compressor clutch click?
YES - Go to step 11.
NO - Go to step 21.
11. Disconnect the jumper wire.
12. Turn the ignition switch to ON (II).
13. Measure the voltage between A/C compressor clutch relay 4P socket terminal No. 4 and body ground.
Is there battery voltage?
YES - Go to step 14.
NO - Repair open in the wire between the No. 10 (7.5 A) fuse in the under-dash fuse/relay box and the A/C compressor clutch relay.
14. Turn the ignition switch to LOCK (0).
15. Reinstall the A/C compressor clutch relay.
16. Make sure the A/C switch is OFF.
17. Jump the SCS line with the HDS.
NOTE: This step must be done to protect the engine/powertrain control module (ECM/PCM) from damage.
18. Disconnect ECM/PCM connector A (49P).
19. Connect the ECM/PCM connector A (49P) terminal No. 15 to body ground with a jumper wire.
20. Turn the ignition switch to ON (II).
Does the A/C compressor click?
YES - Check for loose wires or poor connections at ECM/PCM connector A (49P). If the connections are good, substitute a known-good ECM/PCM, and recheck. If the symptom/indication goes away, replace the original ECM/PCM. Service and Repair
NO - Repair open in the wire between the A/C compressor clutch relay and the ECM/PCM.
21. Disconnect the jumper wire.
22. Disconnect the A/C compressor clutch 3P connector.
23. Check for continuity between A/C compressor clutch relay 4P socket terminal No. 2 and A/C compressor clutch 3P connector terminal No. 2.
Is there continuity?
YES - Check the A/C compressor clutch clearance, the thermal protector circuit, and the A/C compressor clutch field coil. Testing and Inspection
NO - Repair open in the wire between the A/C compressor clutch relay and the A/C compressor clutch.
