See also:

Sound output
Switching on/off When the ignition is switched off: press ON/OFF button on the radio. Muting When the ignition is switched on or the engine is running: press the ON/OFF button on the radio. ...

For US customers
The following only applies to vehicles owned and operated in the US. If you believe that your vehicle has a defect which could cause a crash or could cause injury or death, you should immediate ...

Switching the system on/off
Switching off At the lowest fan speed, press the left side of the button on the driver's side. Switching on Press any button. ...