• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Mirror Heating Element Control | B1640 02 | 1 | B1640 01 | -- |
Low Reference | -- | 1 | 1 | -- |
1. Heated Mirror Malfunction |
The outside rearview mirrors heat during the defrost/defog cycles for the rear window. The heated mirrors are connected to the driver door module (DDM) and the passenger door module (PDM). The DDM and the PDM receive a GMLAN serial data message from the HVAC control module indicating the rear defogger has been activated. The DDM and PDM examine information from the body control module (BCM) to determine if vehicle conditions are correct for the heated mirrors function to be activated. If conditions are correct, the DDM and PDM will command there respective heated mirrors ON.
Outside Rearview Mirror Schematics
Outside Mirror Description and Operation
Control Module References for scan tool information.
⇒ | If the rear window defogger indicator does not illuminate, refer to Rear Window Defogger Malfunction. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp is always ON, test the control circuit terminal 7 for a short to voltage. If the circuit tests normal, replace the DDM. |
⇒ | If the test lamp is always OFF, test the control circuit terminal 7 for a short to ground or an open/high resistance. If the circuit tests normal, replace the DDM. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp is always ON, test the control circuit terminal 7 for a short to voltage. If the circuit tests normal, replace the PDM. |
⇒ | If the test lamp is always OFF, test the control circuit terminal 7 for a short to ground or an open/high resistance. If the circuit tests normal, replace the PDM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for DDM or PDM replacement, setup, and programming |