Circuit/System Description
WARNING: This page is about a different car, the 2007 Pontiac G5 Pursuit, 2007 Pontiac G5, and 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The outside rearview mirror switch supplies both voltage and ground to the outside rearview mirror motors. When the outside rearview mirror switch is being pressed the switch supplies the voltage and ground to the proper circuits to engage the proper mirror motor.