Mercedes-Benz 2009 M-Class Operator's Manual page 183

Air vents
G Warning!
When operating the climate control, the air
that enters the passenger compartment
through the air vents can be very hot or very
cold (depending on the set temperature).
This may cause burns or frostbite to
unprotected skin in the immediate area of
the air vents.
Always keep sufficient distance between
unprotected parts of the body and the air
vents. If necessary, use the air distribution
adjustment to direct the air to air vents in
the vehicle interior that are not in the
immediate area of unprotected skin.
For best possible performance of the climate
control:
X
Keep the air intake grille in front of the
windshield free of snow, leaves, sticks, and
any other debris.
X
Always keep all air vents and grilles in the
passenger compartment free from
obstruction.
i For draft-free ventilation, move the
adjustable center and side air vents to the
middle position.
Overview of climate control system functions and air vents
Center air vents
Left center air vent, adjustable
1
Right center air vent, adjustable
2
Thumbwheel for air volume control for
3
adjustable right center air vent
Thumbwheel for air volume control for
4
adjustable left center air vent
X
Opening/closing: Turn thumbwheels
and in the required direction.
4
Controls in detail
Side air vents
Example illustration driver's side
Left side defroster air vent, fixed
1
Left side air vent, adjustable
2
Thumbwheel for air volume control for
3
adjustable left side air vent
X
Opening/closing: Turn thumbwheel
the required direction.
3
in
3
Z
181