Sunroof / Moonroof: Description and Operation
Sunroof Description and Operation
The slide sunroof consists of a moving glass panel and a manual sunshade. With the spoiler sunroof system, the glass slides over the top of vehicle's roof. The glass is controlled by an integrated motor/controller. The sunshade has a mechanical connection to the glass causing it to open with the glass and keeping it from closing more than the glass.
The electrical portion of the slide sunroof system consists of:
* Body control module (BCM)
* Sunroof glass control module
* Sunroof control switch assembly
* Local interconnected network (LIN-Bus)
The sunroof electrical system uses a master/slave configuration utilizing a LIN-Bus based system for communication. The BCM is designated as the master, while the sunroof control module is configured as the slave.
As the system master, the BCM uses the LIN-Bus communication bus to enable or disable sunroof operation, communicate vehicle information to the sunroof controller, and request sunroof movement. The sunroof controller provides system status and diagnostic information to the BCM for diagnostic reporting and operational purposes.
The sunroof glass is controlled by a 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 LIN-Bus message commands from the system master.
The operational calibrations for the sunroof integrated motor/controller are loaded over the LIN-Bus communication bus by the sunroof system master, the BCM.
Sunroof Glass Control Switch
The sunroof control switch is connected directly to the controller. The sliding glass switch provide detent positions for open, express open, off, and close. The control switch completes the circuit between two signals provided by the control module, a reference ground input and a pull-up voltage provided by an analog to digital switch input. The control switch place a different resistor ladder network in the circuit depending on the function selected. The controllers analog to digital switch input reads the resulting voltage range and determines the appropriate function.
System Protection Functions
Normal operation of the sunroof system may be altered by one of the following events.
Motor stall
If the sunroof is moving in the open or close direction and stops moving for 350 ms while the switch or LIN-Bus command is active, the motor shall be turned off to prevent overheating.
Sunroof System Thermal Protection
The sunroof controllers have a thermal protection algorithm to protect the sunroof controller and motor from damage due to overheating conditions resulting from immoderately switch actuations. The thermal protection algorithm will cause any new sunroof open commands to be ignored until the motor is allowed to cool. A number of close requests during an over temperature condition will be allowed.
Sunroof Operation
Sliding Class
Normal Open
When the sunroof sliding glass switch is held in the OPEN position, the sunroof will begin opening. Motion will continue until the switch returns to the OFF state.
Express Open
When the sunroof control switch transitions to the EXPRESS OPEN state, the sunroof will express open until the controller determines the sunroof has reached the comfort stop position or the fully OPEN position, the switch transitions to another state after first returning to the OFF position.
Normal Close
When the sunroof switch is in the CLOSE state, the controller will begin moving the sunroof in the close direction. The EXPRESS CLOSE operation is not available.