Test A: Isolation Test
1. Remove the A/C Compressor Control Relay and check the voltage at the following terminals of the harness connector using a test lamp. If both checks are good, proceed to step 4.Test A Isolation Test Part 1 Of 3:
2. If test lamp does not light on terminal A, check circuits 495 and 639. Idle Speed Power Steering Pressure Switch should be closed.
^ If switch is open, replace it.
3. Jumper the Pressure Cycling Switch connector.
^ If test lamp now lights at terminal B of A/C Compressor Control Relay, check refrigerant charge. If refrigerant charge is normal, 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.
4. With the A/C Compressor Control Relay removed, connect a fused jumper between terminals B and D of the harness connector.
Test A Isolation Test Part 2 Of 3:
5. Start engine. Connect a test lamp between terminals A and C of the A/C Compressor Control Relay harness connector.
