A/C Heater Control Illumination Inoperative - MTC

*A/C HEATER CONTROL ILLUMINATION INOPERATIVE - MTC

For a complete wiring diagram refer to Diagrams/Electrical.

- When Monitored:

Possible Causes

- Set Condition:

Possible Causes





Diagnostic Test

1. ACTIVE HVAC DTC(S) PRESENT

Turn the ignition on.

With the scan tool, read active HVAC DTCs.

Does the scan tool display any DTCs?

Yes

- Return to the Heating & A/C symptom list and choose the symptom(s).
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 2

2. INSTRUMENT CLUSTER (EMIC) DTC(S) PRESENT

Turn the ignition on.

With the scan tool, read Instrument Cluster DTCs.

Does scan tool display any DTCs?

Yes

- Refer to the Instrument Cluster category for the related symptom(s).
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 3

3. A/C HEATER CONTROL

Turn the ignition off.

Rotate the Panel Lamps Dimmer switch to the off position.

Disconnect the A/C Heater Control C1 harness connector.

Turn the park lamps on.

Measure the voltage of the Panel Lamps Driver circuit while rotating the Panel Lamps Dimmer switch from the off position to the full brightness position.

Does the voltage change from approximately 4.5 volts to 11.5 volts?

Yes

- Replace the A/C Heater Control.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 4

4. PANEL LAMPS DRIVER CIRCUIT OPEN

Disconnect the Instrument Cluster C1 harness connector.

Measure the resistance of the Panel Lamps Driver circuit between the A/C Heater Control C1 harness connector and the Instrument Cluster C1 harness connector.

Does the ohm meter read open circuit?

Yes

- Repair the Panel Lamps Driver circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Replace the Instrument Cluster (EMIC).
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test