Mercedes-Benz 2009 E-Class Operator's Manual page 190

Controls in detail
Climate control system
i For draft-free ventilation, move the
adjustable center and side air vents to the
middle position.
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 upward or downward.
4
188
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
upward or downward.
3
Rear center console air vents
Example illustration: Dual-zone automatic climate
control
Left rear center air vent, adjustable
1
Right rear center air vent, adjustable
2
Thumbwheel for air volume control for
3
right rear center air vent
3
Thumbwheel for air volume control for left
4
rear center air vent
X
Opening/closing: Turn thumbwheel
upward or downward.
4
or
3