The driver door module (DDM) and passenger door module (PDM) each provide motor control output functions for their respective mirrors. These output controls allow each door module to command their respective power mirrors in horizontal and vertical positions. The power mirror switch is integrated into DDM. When the DDM detects an active mirror command from the power mirror switch, the DDM will send a GMLAN serial data message to the PDM. Each door module will command there respective mirror motor in the appropriate direction by applying ground or voltage to the control circuit, depending on the desired mirror position.

The outside rearview mirror adjustment switches are an integrated part of the driver door module (DDM). The Mirror Select Switch is used to select which mirror, driver or passenger, is to be adjusted. The Mirror Position Switch is used to move the mirror that has been selected for adjustment to the desired position. The DDM reports the activity of these switches to the passenger door module (PDM) via GMLAN serial data circuit.

On vehicles that have the memory mirrors feature, the DDM is also wired to, and receives direct signal inputs from the memory function switch. For more information concerning the memory function switch refer to Memory Seats Description and Operation.

Each mirror has 2 reversible motors for position adjustment; the vertical motor and the horizontal motor. Each reversible motor is wired to its associated door module through 2 motor control circuits. The door modules control the reversible motors by applying battery voltage and ground to these 2 motor control circuits. The door module reverses the polarity of the voltage and ground it applies to these 2 circuits in order to run the motor in opposite directions. For example, to run the mirror in the Up direction, the door module applies voltage to the mirror motor up control circuit, and ground to the mirror motor down control circuit. To run the mirror in the opposite Down direction, the module reverses the polarity, supplying voltage to the down control circuit, and ground to the up control circuit.

The vehicle may be equipped with the memory mirrors feature. However, Personalization in the Setup menu of the driver information center (DIC) must be in the active state for memory mirrors to operate. A check mark appearing after the word Personalization on the display screen indicates that the feature is active.

The driver door module (DDM) and passenger door module (PDM) receive mirror position signals from the mirror horizontal and vertical position sensors. These signals are used by the door modules for memory recall functions of the driver and passenger mirrors. The door modules command the mirror memory settings based upon the voltage level received back from the position sensors. Each door module provides a 5 volt supply, a signal, and ground circuit for each of the position sensors. The horizontal and vertical position sensors are variable resistors that the door modules monitor voltage levels across. When a memory setting is recalled, the door modules command the mirror motors in the appropriate directions until the stored position sensor voltage levels are achieved. The DDM and PDM monitor the signal circuits to determine if the voltage level is out of range.

When mirror positions are programmed into the personalization package, the front door modules store the positions indicated by the feedback voltages of the position sensors. When a memory recall is requested, the door modules compare the feedback voltages indicated by the current mirror positions to the stored feedback voltages. The door modules then move the mirrors until the current feedback voltages match the stored feedback voltage levels.

The vehicle is equipped with the parallel parking mode feature. For this feature, the front passenger door module (PDM) communicates with the powertrain control module (PCM) over the GMLAN serial data circuit. When the gear selector is shifted to reverse, the PCM transmits this status via a GMLAN message to the PDM. The PDM then applies voltage and ground to the vertical motor of the RH outside rearview mirror to tilt the mirror down 7 degrees. This allows the driver to see the curb while parallel parking. When the gear selector is shifted out of reverse, the PDM powers the vertical mirror motor to return the mirror to its previous position.

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.

This feature allows the operator to simultaneously retract both mirrors to a fully folded position. The driver door module (DDM) contains the power folding mirrors switch and, each mirror contains an additional power folding mirror motor. The DDM sends a GMLAN serial data message to the passenger door module (PDM) when the power folding mirror switch is activated to the retract or extend positions. When the power folding switch is activated to the fold position, the DDM and PDM respond by applying battery voltage and ground to there respective power folding mirror control circuits in order to retract the mirrors. When the switch is activated to unfold the mirrors, the DDM and PDM reverse the polarity of the voltage and ground applied to the motors in order to move both mirrors to the fully extended position.