The driver door module (DDM) and passenger door module (PDM) supply battery voltage to the mirror heating element supply voltage circuit upon receipt of a class 2 message from the body control module (BCM) indicating that the rear defrost system is active. The DDM and PDM also supply a constant ground for the mirror heating elements.
This diagnostic procedure supports the following DTCs:
• | DTC B1640 Left Front Mirror Heater Circuit |
• | DTC B1645 Right Front Mirror Heater Circuit |
• | System voltage between 9-16 volts |
• | Ignition switch is in the ON position |
When the DDM and PDM supply battery voltage to the mirror heating element supply voltage circuit and its shorted to ground.
The DDM and PDM will ignore the class 2 message and stop supplying battery voltage on the shorted circuit.
When the short circuit is no longer present, the DDM/PDM will clear the current DTC and store the DTC as a history DTC. The history DTC will clear after 50 fault free ignition cycles or in response to a scan tool command.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: Outside Rearview Mirror Schematics Connector End View Reference: Mirror Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Does DTC B1640 or B1645 set as current in the driver door module (DDM) or passenger door module (PDM)? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections |
3 |
Does DTC B1640 or B1645 set as current in the DDM or PDM? | Go to Step 5 | Go to Step 4 |
4 | Inspect for poor connections at the heated mirror. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 8 | Go to Step 6 |
5 | Inspect for poor connections at the harness connector of the appropriate door module . Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 8 | Go to Step 7 |
6 | Replace the heated mirror. Refer to Outside Rearview Mirror Replacement . Did you complete the replacement? | Go to Step 8 | -- |
7 | Replace the appropriate door module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 8 | -- |
8 |
Does the DTC reset? | Go to Step 2 | System OK |