See also:

Remove attached parts following use
Remove unneeded auxiliary mirrors, roof or rear luggage racks after use. Attached parts on the vehicle impair the aerodynamics and increase the fuel consumption. ...

Releasing the parking brake manually
In the event of an electrical power loss or electrical malfunction, you can release the parking brake manually. Secure the vehicle against rolling Before releasing the parking brake manually, ...

What to do if...
Only a black screen is visible. Switch on the system. There are no options available on the screen. Switch over between the display screens. Radio stations or TV channels are grayed out ...