Circuit/System Description
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The sunroof control module supplies each of the sunroof switch signal circuits with a 12-volt reference. When a switch is pressed the signal circuit is pulled low signaling the sunroof open or close request. The sunroof control module determines the motor direction based on inputs received from the sunroof switch. When the sunroof control modules reverse the polarity of the applied voltage, the motor reverses direction.