A/C Compressor Clutch Circuit Troubleshooting

NOTE:


1.Check the No. 29 (10 A) fuse in the under-hood fuse/relay box, and the No. 14 (10 A) fuse in the under-dash fuse/relay box.

Are the fuses OK?


YES - Go to 2.


NO - Replace the fuse(s), and recheck.n


2.Check the engine coolant temperature and idle speed (use the HDS PGM-FI data list if possible).

ECT Sensor 76-90 °C (169-194 °F) 
RPM (min-1More than 850 

Are the coolant temperature and idle speed OK?


YES - Go to 3.


NO - Troubleshoot and repair the cause of the high engine coolant temperature or low idle.n


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

Is the relay OK?


YES - Go to 4.


NO - Replace the A/C  compressor clutch relay.n

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

 

Is there battery voltage?


YES - Go to 5.


NO - Replace the under-hood fuse/relay box.n


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

 

Does the A/C compressor clutch click?


YES - Go to 6.


NO - Go to 15.


6.Disconnect the jumper wire.

7.Turn the ignition switch ON (II).

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

 

Is there battery voltage?


YES - Go to 9.


NO - Repair open in the wire between the No. 14 fuse in the under-dash fuse/relay box and the A/C compressor clutch relay socket.n


9.Turn the ignition switch OFF.

10.Reinstall the A/C compressor clutch relay.

11.Make sure the A/C switch is OFF.

12.Turn the ignition switch ON (II).

13.Substitute a known-good ECM.

14.Turn the ignition switch ON (II) and set the A/C button and fan control dial to ON.

Does the A/C compressor come on?


YES - Check for loose wires or poor connections at ECM connector No. 2 (58P). If the connections are good, check the ECM grounds. If the grounds are good, replace the original ECM.n


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

15.Disconnect the jumper wire.

16.Disconnect the A/C compressor clutch 1P connector.

17.Check for continuity between the No. 2 terminal of the A/C compressor clutch relay 4P socket and the No. 1 terminal of the A/C compressor clutch 1P connector.

 

Is there continuity?


YES - Check the A/C compressor clutch clearance, the thermal protector, and the A/C compressor clutch field coil.n


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