See also:

Activating HDC
Press the button; the LED above the button lights up. ...

Switching on/off manually
Press the button. ▷ On: the LED lights up. ▷ Off: the LED goes out. If Top View is displayed, switch on the backup camera via the iDrive, ...

Safety belt reminder for the driver's and front passenger seat
The indicator lamp flashes or lights up and a signal sounds. Make sure that the safety belts are positioned correctly. The safety belt reminder is active at speeds above approx. 5 mph/8 km/h ...