Mirrors: Description and Operation

REAR VIEW MIRRORS

PRINCIPLES OF OPERATION

The exterior mirrors are controlled by the exterior rear view mirror control switch. The switch supplies power and ground to the selected exterior mirror motor in order to adjust the mirror to the desired position.

Memory Exterior Mirrors
The memory exterior mirrors are controlled by the exterior mirror control switch. The switch supplies power to the driver seat module (DSM). The DSM supplies power and ground to the selected exterior mirror motor in order to adjust the mirror to the desired position. The DSM will store two positions of the exterior mirror and the position is recalled using the memory set switch or remote transmitter.

Heated Exterior Mirrors with Turn Signal
The heated exterior mirrors will only function when the heated rear window is operating. There is no separate control for heated exterior mirrors. They function anytime the heated rear window is ON.

The heated exterior mirror power is supplied through the heated rear window relay. A separate bussed electrical center (BEC) fuse isolates the heated exterior mirrors from the heated rear window in the event of a concern.

Auto-Dimming Interior Rear View Mirror
The automatic dimming feature darkens the interior rear view mirror whenever the front ambient light sensor detects low outside light and glare reaches the light sensor (photo cell) located inside the mirror. The interior rear view mirror starts to return to the normal view once the glare goes away.

The interior rear view mirror reverse input is supplied by a hard-wired circuit from the SJB. When REVERSE is selected the SJB will receive the PRNDL message over the network from the PCM indicating reverse has been selected. The SJB will then supply a power signal to the interior rear view mirror causing the mirror to cancel any dimming function currently operating and return to a full bright status. When the gear selector is moved out of REVERSE the mirror returns to normal operation and resumes any interrupted dimming functions.

If the SJB does not receive the PRNDL information from the PCM, a communication DTC will be logged. As a default, the SJB will supply power to the dimming circuit preventing the automatic dimming function from operating until the message and communication is restored.

The reverse message supplied to the SJB has a time delay before the message is sent by the PCM. This delay allows for the gear selector to be moved through REVERSE without canceling dimming operations.

This feature is configurable. Make sure the vehicle was built with this function enabled before diagnosing.