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, or hard acceleration.
- 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.
1. Check the No. B10 (7.5 A) and the No. B43 (7.5 A) fuse in the under-dash fuse/relay box.
Are the fuses OK?
YES -
Go to step 2.
NO -
Replace the fuse, and recheck. If the fuses blow again, check for a short in the No. B10 (7.5 A) and No. B43 (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 switch in the PGM-FI Data List with the HDS.
Is the A/C switch on?
YES -
Go to step 7.
NO -
Go to step 6.
6. Using the HDS, confirm the following values in the PGM-FI Data List at idle.
Are all the values within specifications?
YES -
Go to step 7.
NO -
Troubleshoot the value that is not within the specifications.
7. Turn the ignition switch to LOCK (0).
8. Remove the A/C compressor clutch relay from auxiliary under-hood relay box A, 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. 7 and body ground.
Is there battery voltage?
YES -
Go to step 10.
NO -
Repair an open in the wire between the No. B43 (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. 7 and No. 8 with a jumper wire.
Do the A/C compressor clutch click?
YES -
Go to step 11.
NO -
Go to step 22.
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. 16 and body ground.
Is there battery voltage?
YES -
Go to step 14.
NO -
Repair an open in the wire between the No. B10 (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 (ECM)/powertrain control module (PCM) from damage.
18. Disconnect ECM/PCM connector A (44P).
19. Measure the voltage between ECM/PCM connector A (44P) terminal No. 14 and body ground.
Is there 0.5 V or less?
YES -
Faulty A/C compressor clutch relay or short to power on the BLU wire. Repair the faulty part or repair the short, then replace the ECM/PCM Service and Repair.
NO -
Go to step 20.
20. Connect ECM/PCM connector A (44P) terminal No. 14 to body ground with a jumper wire.
21. Turn the ignition switch to ON (II).
Do the A/C compressor click?
YES -
Check for loose wires or poor connections at ECM/PCM connector A (44P). 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.
22. Disconnect the jumper wire.
23. Disconnect the A/C compressor clutch 3P connector.
24. Check for continuity between A/C compressor clutch relay 4P socket terminal No. 8 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.