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Home >> Mercedes Benz >> 2025 >> GLB250 Base >> Repair and Diagnosis >> Body & Frame >> Sun Roof/T-Top/Convertible Top >> Sliding Roof, Soft Top, Top Attachments - 247 Chassis >> Basic Knowledge >> Panoramic Sliding Sunroof Control Unit, Basic Function - GF77.21-P-9891A

Panoramic Sliding Sunroof Control Unit, Basic Function - GF77.21-P-9891A

Model all (CAR) with code 413 (Panoramic sliding sunroof/glass roof) 

General 

Depending on vehicle, the control unit of the panoramic sliding sunroof is either a separate control unit or forms the control module of the panoramic sliding sunroof together with drive unit.

Vehicles with separate control unit 

Fig 1: Panoramic Sliding Sunroof Control Unit Components Location - Model All (Car) With Code 413 (Vehicles With Separate Control Unit)
G14136608Courtesy of MERCEDES-BENZ USA

Vehicles with integrated control unit 

Fig 2: Panoramic Sliding Sunroof Control Unit Components Location - Model All (Car) With Code 413 (Vehicles With Integrated Control Unit)
G14136609Courtesy of MERCEDES-BENZ USA

Location 

The panoramic sliding sunroof control unit or the panoramic sliding sunroof control module is located on the front roof frame.

Task 

The panoramic sliding sunroof control unit controls the movements of the panoramic sliding sunroof and the panoramic sliding sunroof roller sunblind via the electric motor of the respective drive unit and processes the following information, among other things, for this purpose:

The panoramic sliding sunroof control unit is connected to the network architecture of the vehicle. It transmits information on the current position and movement of the panoramic sliding sunroof and the panoramic sliding sunroof roller sunblind via the network architecture.

Overheating protection 

The panoramic sliding sunroof control unit protects the electric motors of the panoramic sliding sunroof drive unit and the panoramic sliding sunroof roller sunblind drive unit from overheating. The temperature of the corresponding electric motor is calculated by considering the supply voltage, the flowing current, the duration of actuation, and the outside temperature. If the overheating protection was triggered, the actuation of the affected electric motor is disabled for a minimum cooling time.

IMPORTANTException 

The overheating protection function does not operate during roof reversal (after a blockage is detected).