The outside mirror control switch is contained within the driver door switch assembly (DDSA). The DDSA contains a microprocessor which takes the signal generated by the outside mirror control switch and assigns a digital message to the switch signal. The DDSA sends this message via the GMLAN serial data circuit to the driver door module (DDM) to move the left mirror or the passenger front door module (PDM) to move the right mirror. The DDM or PDM then applies voltage and ground to the appropriate circuits of the appropriate mirror motor to move the mirror vertically and/or horizontally. For more detailed information concerning power outside mirror operation refer to Outside Mirror Description and Operation .

This diagnostic procedure supports the following DTCs:

This vehicle has DTCs which include DTC symptoms. For more information on DTC symptoms, refer to DTC Symptom Description in Vehicle DTC Information.

The DDM and the DDSA must be powered.

The DDSA communicates with the DDM via GMLAN that the outside power mirror control switch is closed for more than 30 continuous seconds.

The DDSA deactivates and ignores inputs from the failed switch contacts and stops sending messages for this switch to the DDM. The DDSA will continue to respond to inputs from other non-failed switch contacts.

Important: When a contact for a mirror position has failed, it will affect both mirrors.

Thoroughly inspect the wiring and connectors. An incomplete inspection of the wiring and connectors may result in misdiagnosis causing part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.