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) or Passenger Door Module (PDM) controls the mirror horizontal and vertical motors through the use of bi-directional motor controls. When the mirror is commanded up and down, voltage or ground is supplied to the mirror vertical motor through the mirror motor vertical control circuit and voltage or ground is supplied through the mirror motor common control circuit.

Horizontal controls operate in the same manner with the mirror motor horizontal control circuit supplying voltage or ground and the mirror motor common control circuit suppling voltage or ground to the mirror horizontal motor when the mirror is commanded right and left.

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.