Operation CHARM: Car repair manuals for everyone.

Control Module HVAC: Testing and Inspection

Operation Check




PART 1 OF 2




PART 2 OF 2

1. Run engine, and operate A/C system.
2. Connect the voltmeter from harness side.
3. Check thermo control amp. operation shown in the table.

Power supply circuit check




PART 1 OF 2




PART 2 OF 2

Check power supply circuit for thermo control amp. with ignition switch ON.
1. Disconnect thermo control amp. harness connector.
2. Connect voltmeter from harness side.
3. Measure voltage across terminal (1) and body ground.

Ground circuit check




PART 1 OF 2




PART 2 OF 2

Turn A/C and fan switches ON. Check body ground circuit for thermo control amp.
1. Disconnect thermo control amp. harness connector.
2. Connect ohmmeter from harness side.
3. Check for continuity between terminal (2) and body ground.