Windows fogged up on the inside
Activate the cooling with air
dehumidification function 
.
Activate automatic mode
.
If the windows continue to fog up,
activate the defrosting function.
You should only select this
setting until
the windshield is clear again.
See also:
Working on the vehicle
WARNING
When working on the vehicle, engage the
electronic parking brake and shift the
automatic transmission into park position P.
Otherwise the vehicle could roll away which
could result in ...
Setting the rear-compartment air
distribution using the rear control panel
Turn the SmartKey to position 2 in the
ignition lock.
Press rocker switch 13 or 16 up or down
repeatedly until the desired
air distribution symbol is shown in the
display. ...
Snow chains
For safety reasons, Mercedes-Benz
recommends that you only use snow chains
which have been specially approved for your
vehicle by Mercedes-Benz, or are of a
corresponding standard of quality.
...