Sunroof Description and Operation: Notes

The sunroof system consists of a moving glass panel and a 2nd fixed glass panel located just behind the moving glass panel. The moving glass component slides over the top of the fixed glass, and the roof panel. There is also a power roller sunroof which covers both glass panels. The electrical portion of the system controls the opening and closing of the sunroof glass and the power roller sunroof. The ignition must be in ON/RUN/START, ACC/ACCESSORY, or in retained accessory power (RAP) to operate the sunroof.

The electrical portion of the spoiler sunroof system consists of:

• Body control module (BCM)
• Sunroof control module

The BCM communicates with the sunroof glass control module to enable or disable sunroof operation. The sunroof control modules provide system status and diagnostic information to the BCM for diagnostic reporting and operational purposes.

The sunroof glass is controlled by its own integrated motor/controller containing the necessary electronics, motor, hall effect position sensors, as well as the interface to the driver control switches. The motor/controller is capable of controlling motion based on control switch activation and message commands from the BCM.

There are times when the sunroof operation are dependent on each other (see below). This dependency is controlled by the BCM.

Fig 1: Sunroof Block Diagram

Courtesy of GENERAL MOTORS COMPANY