Activating/deactivating
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 
rocker switch up or
down.
The indicator lamp in the rocker
switch lights up or goes out.
See also:
Vehicle data, GL 450
The data stated here refers specifically to a
vehicle with standard equipment. Consult an
authorized Mercedes-Benz Center for the
data for all vehicle variants and trim levels.
...
Problems with your vehicle
If you should experience a problem with your
vehicle, particularly one that you believe may
affect its safe operation, we urge you to
contact an authorized Mercedes-Benz Center
immediately to have ...
Basic telephone menu (Bluetooth® interface)
To call up the telephone menu: press the
function button once or twice.
If the mobile phone is ready for use, the
following display appears:
Example display: telephone basic menu (Bluetooth® ...