Activating/deactivating

Any accumulation of snow and ice should be WARNING
Any accumulation of snow and ice should be removed from the rear window before driving.
Visibility could otherwise be impaired, endangering you and others.

The rear window defroster has a high current draw. You should therefore switch it off as soon as the window is clear as it only switches off automatically after several minutes.
If the battery voltage is too low, the rear window defroster may switch off.
- Turn the SmartKey to position 2 in the ignition lock.
- Press the The indicator lamp in the  button button.
The indicator lamp in the lights button lights up or goes out.

    See also:

    Important safety notes
    For reasons of safety, Mercedes-Benz recommends that you drive with the lights switched on even during the daytime. In some countries, operation of the headlamps varies due to legal requiremen ...

    Rocking the vehicle free
    Rocking the vehicle free by shifting back and forth between transmission positions D and R can help to free a vehicle that has become stuck in mud or snow. The engine management system of the ...

    Muscular Moves, Eventually
    The turbo-diesel GL320 Bluetec has additional exhaust treatments to cut soot and nitrogen oxide emissions — technology last year's diesel GL320 CDI lacked, which is why California and several Nort ...