Principles Of Operation

Rear View Mirrors - Exterior

Principles of Operation

The LH and RH exterior mirror motors are controlled by the exterior rear view mirror control switch. Adjusting the exterior control switch to the LH or RH position determines which exterior mirror motor will be controlled. Power is supplied to the exterior mirror switch from the Central Junction Box (CJB). DTCs are only capable of setting on vehicles equipped with memory exterior rear view mirrors.

The exterior mirrors use a jumper harness between the vehicle wire harness connector and the exterior mirror motor. The exterior mirror jumper harness is integral to the exterior mirror. If a concern with the exterior mirror jumper harness exists and cannot be repaired, a new exterior mirror must be installed.

Memory Exterior Mirrors

The memory mirror function recalls the preferred positioning of the exterior mirror motors when the transmission is in the PARK or NEUTRAL position and the door-mounted memory switches, Remote Keyless Entry (RKE) transmitter or RKE keypad are activated.

The Driver Door Module (DDM) monitors the exterior mirror control switch. When the exterior mirror control switch is activated, the DDM receives an input signal and then sends a Standard Corporate Protocol (SCP) message to the Driver Seat Module (DSM). The DSM will then apply voltage and ground to the requested exterior mirror motor to move the exterior mirror motor to the desired position.

Each exterior mirror is equipped with a potentiometer, which the DSM uses to monitor the LH and RH mirror motor positions. When a mirror motor position is stored in the DSM, the DSM will retain this position in memory for future recall. The position of the mirror motors are stored within the DSM memory as long as the DSM retains power. When a memory position is recalled by the operator, the DSM will apply voltage and ground the exterior mirror motors simultaneously and monitor the potentiometer circuits. When the stored memory position is reached, the DSM will remove the voltage and ground from the exterior mirror motors. If the exterior mirror control switch is operated during a memory recall, the DSM will stop the memory recall and respond to the exterior mirror control switch command.

For information on the DDM, refer to Body Control Systems.

For information on the DSM and Memory Position Programming, refer to Seats.

Heated Exterior Mirror

The rear window defrost switch controls the operation of the heated exterior mirror glass. The heated exterior mirror glass only operates when the rear window defrost system is ON. The heated exterior mirror power is supplied by the rear window defrost relay through Battery Junction Box (BJB) fuse 23 (10A), which isolates the heated exterior mirror system from the rear window defrost system in the event of a concern.

For information on the rear window defrost system, refer to Windows and Glass.

LH Auto-Dimming Mirror

The LH exterior mirror auto-dimming feature (feature also present in the interior rear view mirror) automatically reduces the glare caused by headlamps reflecting in the mirror. The auto-dimming feature is disabled when the vehicle is in REVERSE. Power is supplied to the interior auto-dimming mirror when the ignition is in the RUN or ACC position. The interior mirror controls the LH exterior mirror via the 2 dedicated signal and signal return circuits.

The interior auto-dimming rear view mirror has 2 photoelectric sensors that detect forward and rearward light conditions, and based on those inputs, adjusts the reflectance level of the interior rear view mirror and LH exterior mirror to eliminate unwanted glare. The reflectance level of the mirror glass is variable and depends on the amount of rear glare in relation to ambient light conditions in front of the interior mirror.

When the forward sensor detects daytime conditions, the rearward sensor is inactive and the mirror glass stays in a high-reflectance mode. When the forward sensor detects nighttime conditions, the rearward sensor is active and detects glare from the headlights of vehicles approaching from the rear, or other glare producing light sources. To provide increased visibility when backing up, the interior rear view mirror glass and LH exterior mirror glass will automatically return to a high-reflectance mode whenever the selector lever is placed in REVERSE.

If the forward or rearward sensors are blocked, the auto-dimming interior rear view mirror and LH exterior mirror might not work correctly.

Puddle Lamps

The exterior mirrors may be equipped with puddle lamps, which will illuminate when the interior lights are turned on by opening a door or by pressing the unlock button on the RKE, if equipped.

For information on the mirror-mounted puddle lamps, refer to Lighting and Horns.