A/C Compressor Clutch Circuit Troubleshooting

1.Check the No. 11 (30A) fuse in the under-hood fuse/relay box, and the No. 22 (7.5A) 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 throttle position, and idle speed (use the HDS PGM-FI data list if possible).

Sensor 80-95°C (176-203°F) 
TPS About 0.5 V 
RPM More than 650 

Is the coolant temperature, throttle position, and idle speed OK?


YES - Go to 3.


NO - Troubleshoot and repair the cause of the high engine coolant temperature, low idle, or excessively hight throttle position sensor reading.n


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

Is the relay OK?


YES - Go to 4.


NO - Replace the  compressor clutch relay.n


4.Measure the voltage between the No. 2 terminal of the compressor clutch relay 5P 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 compressor clutch relay 5P socket with a jumper wire.

 

Does the compressor clutch click?


YES - Go to 6.


NO - Go to 14.


6.Disconnect the jumper wire.

7.Turn the ignition switch ON (II).

8.Measure the voltage between the No. 5 terminal of the compressor clutch relay 5P socket and body ground.

 

Is there battery voltage?


YES - Go to 9.n


NO - Repair open in the wire between the No. 22 fuse in the under-dash fuse/relay box and the compressor clutch relay.n

9.Turn the ignition switch OFF.

10.Reinstall the compressor clutch relay.

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

12.Turn the ignition switch ON (II).

13.Measure the voltage between the No. 12 terminal of ECM connector E (40P) and body ground with the ECM connectors connected.

 

Is there battery voltage?


YES - Check for loose wires or poor connections at ECM connector E (40P). If the connections are good, substitute a known-good ECM, and recheck. If the symptom/indication goes away, replace the original  ECM.n


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


14.Disconnect the jumper wire.

15.Disconnect the compressor clutch 1P connector.

16.Check for continuity between the No. 1 terminal of the compressor clutch relay 5P socket and the No. 1 terminal of the compressor clutch 1P connector.

 

Is there continuity?


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


NO - Repair open in the wire between the compressor clutch relay and the compressor clutch.n