Mercedes-Benz 2008 M-Class Operator's Manual page 240

Controls in detail
Power windows
Press and hold button ‹ on the
SmartKey or SmartKey with
KEYLESS-GO* until the windows and
the tilt/sliding sunroof are completely
closed.
Release button ‹ on the SmartKey
or SmartKey with KEYLESS-GO* to
interrupt the closing procedure.
Vehicles with KEYLESS-GO*:
Press and hold the lock button on an
outside door handle ( page 69) until
the windows and the tilt/sliding sun-
roof are completely closed.
Release the lock button on the outside
door handle to interrupt the closing
procedure.
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