Mercedes-Benz 2010 GL-Class Operator's Manual page 176

Overview of climate control system functions and air vents
174
Air vents in the roof liner over the
second-row seats
Vehicles with 3-zone automatic climate control
only
Thumbwheel for air volume control
:
Air vent, adjustable
;
X
Opening/closing: Turn thumbwheels :
upward or downward.
Air vents in the roof liner over the third-
row seats
Vehicles with 3-zone automatic climate control
only
Left air vent, adjustable
:
Right air vent, adjustable
;
Thumbwheel for air volume control for
=
adjustable right air vent
Thumbwheel for air volume control for
?
adjustable left air vent
X
Opening/closing: Turn thumbwheels =
and ? upward or downward.