Heated Mirrors Inoperative

Heated Mirrors Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.



Circuit/System Description

The outside rearview mirrors heat during the defrost/defog cycles for the rear window. The driver door module (DDM) and passenger door module (PDM) control the heated mirror functions. The DDM supplies power and ground to the driver heated mirror and the PDM supplies it to the passenger heated mirror. When the door modules receive a class 2 serial data message from the HVAC control module indicating the rear defogger has been turned ON, both door modules will activate the heated mirror by applying voltage to the heated mirror element feed circuit.


Reference Information
Schematic Reference

Outside Rearview Mirror Schematics (Outside Rearview Mirror Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Outside Mirror Description and Operation (Outside Mirror Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information


Circuit/System Testing

1. Ignition OFF, disconnect the X1 harness connector at the inoperative outside rearview mirror.
2. Test for less than 1.0 ohm of resistance between the ground circuit terminal B and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal E and the ground circuit terminal B.
4. Command the inoperative mirror heater ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the inoperative door control module.


• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the inoperative door control module.

5. If all circuits test normal, test or replace the inoperative outside rearview mirror.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Mirror Replacement (Mirror Replacement)
* Control Module References (Programming and Relearning)for DDM or PDM replacement, setup, and programming