Roof function center (FZD)

The slide/tilt sunroof is controlled and monitored from the roof function center (FZD). The roof function center (FZD) receives signals from other control units for the various functions of the slide/tilt sunroof:

• The Car Access System (CAS) supplies the enabling signal allowing operation of the slide/tilt sunroof
• The footwell module (FRM) supplies signals from the door contacts
• The Junction Box Electronics (JBE) module provides access to Terminal 30B through the roof function center (FZD).

The roof function center (FZD) responds to commands requesting operation of the slide/tilt sunroof by activating the two integral relays. The relays supply the appropriate drive units with voltage.

The roof function center (FZD) monitors the relay contacts to ensure correct operation (glass slide/tilt sunroof panel and sliding headliner). Two hall effect sensors are integrated within each of the drive units. The pulses from the hall effect sensors are employed by the roof function center (FZD) as the basis for calculating travel speeds and operating paths and identifying the direction of rotation. The travel distance required for opening and closing is stored in the roof function center. While traversing this travel distance the drive units generate a specific number of pulses. Consequently, the roof function center (FZD) is able to detect the position of the glass slide/tilt sunroof panel and sliding headliner.

The roof function center (FZD) calculates closing force based on the closing speed. The required mechanical force varies as a function of ambient temperature and as a result of ageing processes. For this reason the closing force required and the parameters for the closing force limiter are adapted for the closing actions in defined distances.

The following slide/tilt sunroof functions integrated in the roof function center (FZD):

• Read in command request
• Controlling and monitoring glass slide/tilt sunroof panel drive motor and sliding headliner drive motor
• Closing force limiter
• Locking protection
• Panic mode
• Load cutoff during starting up (automatic engine start-stop function)
• Locator lighting (terminal 58g) in the slide/tilt sunroof switch
• Initialization.