Mercedes-Benz 2011 R-Class Operator's Manual page 148

Setting the air vents
146
Setting the rear-compartment side air
vents
B-pillar air vent
:
Thumbwheel for B-pillar air vent
;
X
To open/close: turn thumbwheel ; to the
left or right.
Side air vents in the rear compartment (3rd row of
seats)
Defroster vent
:
B-pillar air vent
;
Thumbwheel for B-pillar air vent
=
X
To open/close: turn thumbwheel = up or
down.