GM Service Manual Online
For 1990-2009 cars only

The rear window power sunshade control module contains the logic for extending or retracting the sunshade based on inputs received from the rear window power sunshade switch. The switch is a momentary type, and is located in the overhead console with the power sunroof controls.The module activates the sunshade motor based on the inputs received from the switch. When the Ignition switch is in the ON position, or, when retained accessory power (RAP) is active, voltage is applied to the power sunshade control module via the RAP relay. The sunshade control module controls the sunshade motor direction by changing the polarity of the applied voltage. If the ignition switch is turned to the OFF position while the sunshade is moving, the module enters a "Standby" mode, and the shade will cease to move. The module will remain in the "Standby" mode and the shade will remain in the position it was in when movement ceased, until the module receives another switch activation input. Movement will then resume, but in the opposite direction from the last activation.

The sunshade motor assembly contains the reversible DC drive motor and the gear train used to move the shade material to the desired position. The motor also contains a positive temperature coefficient (PTC) thermal circuit breaker to protect the system from an overload.