GM Service Manual Online
For 1990-2009 cars only

Power Mirror System Components

The power mirror system consists of the following components:

    • Body control module (BCM)
    • Outside rearview mirror switch
    • Mirror selector switch
    • Left outside rearview mirror
    • Right outside rearview mirror
    • PWR MIRROR 2-amp fuse

Each of the outside rearview mirrors contains 2 motors. The vertical motor operates the mirror in the up and down directions, and the horizontal motor operates the mirror in the left and right directions. Each of the outside rearview mirror motors are circuit breaker protected.

Power Mirror System Controls

The outside rearview mirror switch is a 4 position directional switch: Up, Down, Left and Right.

The mirror select switch is a 3 position switch: L, Off and R.

Power Mirror System Operation

The outside rearview mirror switch receives power through the battery positive voltage circuit from the PWR MIRROR 2-amp fuse. The power mirror switch also receives a constant ground.

The 4 positions of the direction switch have dual switch contacts. Each of the contacts are connected to opposing sides of the appropriate power mirror motors through the selector switch. The selector switch completes these circuits depending on the position of the selector switch, L or R.

If the selector switch is placed in the L position and the up switch is depressed, battery positive voltage will be supplied to the left outside rearview mirror vertical motor through the left mirror motor down control circuit and ground through the left mirror motor left control circuit. If the down switch is depressed, battery positive voltage will be supplied to the left outside rearview mirror vertical motor through the left mirror motor left control circuit and ground through the left mirror motor down control circuit.

The remainder of the mirror functions operate in the same manner as described above. Placing the power mirror switch in opposing positions, left/right or up/down, will reverse the polarity to the mirror motor.

Heated Mirrors

Battery positive voltage is supplied through the RBEC BATT1 60-amp fuse in the underhood electrical center to the rear defog relay. With the ignition in the ON position, voltage is supplied to the rear defog relay coil when the rear window defogger switch is activated. This energizes the rear window defogger relay and allows battery positive voltage to the HTD MIRROR 10-amp fuse. The HTD MIRROR fuse provides battery positive voltage to the heated mirrors.