A/C Compressor Clutch Circuit Troubleshooting
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.
- Before doing any symptom troubleshooting, check for powertrain DTCs Initial Inspection and Diagnostic Overview.
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.�
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 an 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 an 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 control module/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 an 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 an open in the wire between the A/C compressor clutch relay and the A/C compressor clutch.�