Sunroof / Moonroof: Description and Operation

Sunroof Description and Operation

Power Sunroof System Components

The Power Sunroof System consists of the following components:

* Sunroof control module
* Sunroof switch
* Sunroof glass, tilt/slide style, with glass sliding between the headliner and roof
* Rail and track assembly upon which the sunroof glass rides
* SUNROOF Fuse 30 A
* Body control module (BCM)

Power and Grounds

Battery positive voltage is supplied at all times to the sunroof control module assembly from the 30 A SUNROOF fuse located in the underhood fuse block. Ground is supplied to the sunroof control module through the module ground circuit and G200.

Ground is supplied to the sunroof switch through the switch ground circuit and G200.

Power Sunroof Operation

The power sunroof system will operate with the ignition switch turned to Accessory or RUN positions, this allows for retained accessory power (RAP) control of the sunroof through the BCM. Once the ignition switch is turned to OFF the sunroof will continue to operate until any door is opened or when the RAP timer reaches its shut-off limit. For a description and operation of the RAP operation, refer to Retained Accessory Power Description and Operation (Retained Accessory Power Description and Operation).

Sunroof Switch

The sunroof switch, located in the front center of the headliner, contains two rocker type switches that are used to control the following sunroof functions:

* Roof express open/close
* Roof open/close
* Vent open/close

Express Open

The express open will only operate with the sunroof in the fully closed or partially open position. To express open the sunroof glass, momentarily press the sunroof switch to the second rearward position once. This will apply the sunroof switch low reference circuit to both the sunroof switch express signal circuit and to the sunroof switch open signal circuit (12-volt references) inputs, pulling them to 0 volts momentarily. The momentary transition inputs to the sunroof module indicates an express open request. Once the express open has been initiated, the sunroof motor/module assembly will drive the motor in the open direction, slightly lowering the rear edge of the sunroof glass, then sliding open with the sunshade, allowing the wind deflector to raise upward. The sunroof glass will continue to express open until:

* The sunroof glass reaches the requested full open position.
* Activation of the sunroof switch (in any direction) to stop the sunroof glass in a desired position other than the express open position.
* Motor stall is sensed because the sunroof glass is being obstructed.
* The operation time-out expires, 15 seconds after the initiation of the express open feature has been requested.

To Open

Opening the sunroof can be done from any position between fully closed and partially open. To open the sunroof glass, press and hold the sunroof switch to the first rearward position. This will apply the sunroof switch low reference circuit to the sunroof switch open vent signal circuit (12-volt reference) input, pulling the reference voltage to 0 volts. The constant low (0 volts) input to the sunroof module indicates an open request. Once the open has been initiated, the sunroof motor/module assembly will drive the motor in the open direction, slightly lowering the rear edge of the sunroof glass, then sliding open with the sunshade, allowing the wind deflector to raise upward. The sunroof glass will continue to open until the sunroof motion is terminated by either:

* The sunroof glass reaches the full open position.
* Releasing of the sunroof switch. The sunroof may be left in any position between fully open and fully closed.

To Vent Open

Opening the sunroof glass, to the vent position, can be done when it is between fully closed and partially vent. To vent open, press and hold the sunroof vent switch rearward. This will apply the sunroof switch low reference circuit to the sunroof switch open vent signal circuit. Holding the sunroof switch in the vent position will cause the sunroof switch open vent signal circuit (12-volt reference) input to be pulled to 0 volts. The constant low input to the sunroof module indicates a vent request. Once the vent request has been initiated, the sunroof motor/module assembly will drive the motor in the closed direction (to vent position) until the sunroof motion is terminated by either:

* The sunroof glass reaches the full vent open position.
* Releasing the sunroof switch.

Closing to the Fully Closed Position

To close the power sunroof from the following positions:

* Open position, press and hold the sunroof switch forward.
* Vent position, press and hold the sunroof vent switch forward.

Holding the sunroof switch to the closed position will apply the sunroof switch low reference circuit to either the sunroof switch close signal or the sunroof switch close vent signal circuit. Holding the sunroof switch to the closed position will cause the sunroof switch close signal or the sunroof switch close vent signal circuit (12 volt reference) to be pulled to 0 volts. The constant low input to the sunroof control module indicates a close request. As the close request has been initiated, the sunroof motor/module assembly will drive the motor to the closed position. As the sunroof glass nears the closed position, the wind deflector will retract, and the rear sunroof glass will raise slightly, then seats to flush with the roof panel. To close the sunshade, this will have to be manually slid closed.