Test A: Isolation Test

1. Remove the A/C Compressor Control Relay and check the voltage at the terminals of the harness connector illustrated in the image using a test lamp.

Test A Isolation Test:

^ If both checks are good, proceed to step 4.

2. If test lamp does not light on terminal A, check circuits 901 and 639. Idle Speed Power Steering Pressure Switch should be closed.

^ If switch is open, replace it.

3. Jumper the Pressure Cycling Switch harness connector.

^ If test lamp now lights at terminal B of A/C Compressor Control Relay, check refrigerant charge. If refrigerant charge is good, replace the Pressure Cycling Switch.

^ If test lamp does not light, check circuit 67 for an open. If circuit 67 is good, reconnect A/C Compressor Control Relay and proceed to A/C Compressor Relay Test.

Test A Isolation Test:

4. With the A/C Compressor Control Relay removed, connect a fixed jumper between terminals B and D of the harness connector.

Test A Isolation Test:

5. Start engine. Connect a test lamp between terminals A and C of the A/C Compressor Control Relay harness connector.