GM Service Manual Online
For 1990-2009 cars only

The sunroof switch controls the position of the sunroof. The sunroof panel may be slid open or closed. The rear of the panel may be tilted up into a vent position.

When the sunroof switch is moved to the OPEN position, the open relay energizes. The open relay performs the following functions:

    • Sends voltage through circuit 127 to the sunroof actuator
    • Grounds circuit 129

This drives the sunroof in one of the following directions:

    • Up (to vent)
    • Back (for sliding)

Operation in the CLOSE position is similar. Before the sunroof opens, the sunroof inspects the limit switches in order to verify what position the sunroof is in.

The sunroof will automatically stop in the following positions:

    • Fully open
    • Vent when opening
    • Closed

Each of these positions is sensed by limit switches. For example, if the roof is closing from the vent position, the close relay will be energized. When the roof is fully closed, this position is recognized. The limit switches set the correct sequence when the sunroof is in the fully closed position. When the limit switches are in the correct sequence, the sunroof module microprocessor recognizes this and the following functions may occur:

    • No voltage is applied to the sunroof actuator
    • The system stops.

In order to continue the operation to the sliding mode, the driver must release the sunroof switch.