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 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. 20 (7.5 A) fuse in the under-hood fuse/relay box and the No. 36 (10 A) fuse in the under-dash fuse/relay box.

Are the fuses OK?
YES - Go to step 2.

NO - Replace the fuses, and recheck. If the fuses blow again, check for a short in the No. 20 (7.5 A) and No. 36 (10 A) fuses circuit.


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. 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. Remove the A/C compressor clutch relay from the under-hood fuse/relay box, and test it. Testing and Inspection

Is the relay OK?
YES - Go to step 8.

NO - Replace the A/C compressor clutch relay.


8. Measure the voltage between the A/C compressor clutch relay 4P socket No. 1 terminal and body ground.

Is there battery voltage?
YES - Go to step 9.

NO - Replace the under-hood fuse/relay box. Under-hood Fuse/Relay Box Removal and Installation






9. Connect the A/C compressor clutch relay 4P socket No. 1 and No. 2 terminals with a jumper wire.

Does the A/C compressor clutch click?
YES - Go to step 10.

NO - Go to step 19.






10. Disconnect the jumper wire.

11. Turn the ignition switch to ON (II).

12. Measure the voltage between the A/C compressor clutch relay 4P socket No. 3 terminal and body ground.

Is there battery voltage?
YES - Go to step 13.

NO - Repair open in the wire between the No. 36 (10 A) fuse in the under-dash fuse/relay box and the A/C compressor clutch relay.






13. Turn the ignition switch to LOCK (0).

14. Reinstall the A/C compressor clutch relay.

15. Jump the SCS line with the HDS.
NOTE: This step must be done to protect the powertrain control module (PCM) from damage.

16. Disconnect PCM connector A (44P).

17. Connect the PCM connector A (44P) No. 14 terminal to body ground with a jumper wire.






18. Turn the ignition switch to ON (II).

Does the A/C compressor click?
YES - Check for loose wires or poor connections at PCM connector A (44P). If the connections are good, check the PCM grounds. If the grounds are good, substitute a known-good PCM, Initial Inspection and Diagnostic Overview and recheck. If the symptom/indication goes away, replace the original PCM. Service and Repair

NO - Repair open in the wire between the A/C compressor clutch relay and the PCM.


19. Disconnect the jumper wire.

20. Disconnect the A/C compressor clutch 3P connector.

21. Check for continuity between the A/C compressor clutch relay 4P socket No. 2 terminal and the A/C compressor clutch 3P connector No. 3 terminal.

Is there continuity?
YES - Check the A/C compressor clutch clearance, and the compressor clutch field coil. Testing and Inspection Repair as needed.

NO - Repair open in the wire between the A/C compressor clutch relay and the A/C compressor clutch.