If this function is switched on, the LED lights up in the following button:

If rear window heating is activated with the ignition switched on, the battery management determines whether or not the battery charge level is sufficient for the rear window heating to be switched on. Otherwise the rear window heating operates when the engine is running, and switches off automatically after about 10 - 20 minutes, depending on the outside temperature.

To switch on the rear window heating permanently, press and hold the or the button for at least two seconds. This setting will be stored for approximately 15 minutes after the ignition is switched off.