GM Service Manual Online
For 1990-2009 cars only

The rear window power sunshade is controlled by the rear window power sunshade module. In order for the sunshade to function, the module must receive an input from the rear window power sunshade switch. Only express movements are available. The sunshade switch is a momentary design type of switch and has two positions available to the operator:

    • Normal off position
    • Momentary sunshade activate position.

The sunshade will only operate when the ignition is in the Run or Accessory modes, or in the ignition off, retained accessory power (RAP) mode. When the system is powered up, the sunshade functions in four different modes.

    • Standby Mode
    • Express Extend
    • Express Retract
    • Express Reverse

Standby Mode

The sunshade is in a standby mode whenever the module is powered up, and the sunshade is not being operated, and no inputs are being received from the sunshade switch.

Express Extend

When the sunshade is down, or, retracted, and the momentary switch is pushed, the module will activate the sunshade motor to move the sunshade to the fully extended position.

Express Retract

When the sunshade is up, or, extended, and the momentary switch is pushed, the module will activate the sunshade motor to move the sunshade to the fully retracted position.

Express Reverse

If the sunshade momentary switch is pressed while the sunshade is already moving, the sunshade will reverse its direction of movement.

Circuit Description

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 module activates the sunshade motor based on the inputs received from the switch. When the Ignition switch is in the ON position, Accessory position, or when RAP is active (key off), voltage is applied to the power sunshade control module. 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 complete its cycle. 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.