See also:

Active seat ventilation
Switching on Press the button once for each ventilation level. The highest level is active when three LEDs are lit. Switching off Press the button longer. The LEDs go out. ...

Switching on automatically
With the engine running or the ignition switched on, shift the selector lever into position R. The image of the rear view camera is displayed when the system has been switched on using iDrive. ...

Ignition on
Automatic transmission: press the Start/Stop button, and do not press on the brake pedal at the same time. Manual-shift transmission: press the Start/Stop button, and do not press on the clutch ...