Circuit/System Description
WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The Driver Door Module (DDM) and Passenger Door Module (PDM) determine the position of the outside rearview mirrors based on inputs from two mirror position sensors, one for vertical position, the other for horizontal position. Five volts is applied to each sensor through a shared 5-volt reference circuit and a shared low reference circuit supplies ground. Each sensor has an individual signal circuit which provides position voltage to the DDM/PDM.