MERCEDES-BENZ R-Class 2012 W251 Owner's Manual

Useful information ............................130
Overview of climate control sys-
tems ................................................... 130
Operating the climate control sys-
tem ..................................................... 134
Setting the air vents .........................141129Climate control

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Please read the information on qualified
specialist workshops ( Y page 24).
Overview of climate control systems
Important safety notes
GWARNING
Severe conditions (e.g. strong air pollution)
may require replacement of the filter before
its scheduled replacement interval. A clogged
filter will reduce the air volume to the interior
and the windows could fog up, impairing
visibility and endangering you and others.
Have a blocked filter replaced at a Mercedes-
Benz Center as soon as possible.
GWARNING
Follow the recommended settings for heating
and cooling given on the following pages.
Otherwise, the windows could fog up,
impairing visibility and endangering you and
others.
The automatic climate control 13
adjusts the
temperature and the humidity of the vehicle
interior and filters undesired substances from
the air.
The automatic climate control 13
is only
operational when the engine is running. 14
Optimum operation is only achieved if you
drive with the side windows and sliding
sunroof/panorama roof with power tilt/
sliding panel closed.
i Ventilate the vehicle for a brief period
during warm weather, e.g. using the
convenience opening feature ( Y page 87).
This will speed up the cooling process and
the desired vehicle interior temperature
will be reached more quickly.
i The integrated filter can filter out most
particles of dust and completely filters out
pollen. A clogged filter reduces the amount
of air supplied to the vehicle interior. For
this reason, you should always observe the
interval for replacing the filter, which is
specified in the Service Booklet. As it
depends on environmental conditions, e.g.
heavy air pollution, the interval may be
shorter than stated in the Service Booklet.13 Canada only.
14 Automatic climate control: the residual heat function can only be activated/deactivated when the ignition
is switched off.130Overview of climate control systemsClimate control

Control panel for dual-zone automatic climate control:To set the temperature, left (Y page 137);To set climate control to automatic ( Y page 136)=To defrost the windshield ( Y page 138)?To increase the airflow ( Y page 138)ATo direct the airflow through the defroster vents ( Y page 138)BTo activate/deactivate cooling with air dehumidification ( Y page 135)CTo set the temperature, right ( Y page 137)DTo switch rear-compartment climate control on/off ( Y page 134)ETo direct the airflow through the center and side air vents ( Y page 138)FTo direct the airflow to the footwells and side air vents ( Y page 138)GTo display the airflow levelHTo reduce the airflow ( Y page 138)ITo switch the rear window defroster on/off ( Y page 139)JTo activate/deactivate air-recirculation mode ( Y page 140)KInterior temperature sensorLTo switch climate control on/off ( Y page 134)Notes on using dual-zone automatic
climate control
The following contains notes and
recommendations on optimum use of dual-
zone automatic climate control.
R Activate climate control using the à and
Á buttons. The indicator lamps in the
à and Á buttons light up.
R Set the temperature to 72 ‡ (22 †).
R Only use the "defrosting" function briefly
until the windshield is clear again.
R Only use "air-recirculation" mode briefly,
e.g. if there are unpleasant outside odorsor when in a tunnel. The windows could
otherwise fog up as, in air-recirculation
mode, no fresh air is drawn into the vehicle.
R Use the residual heat function if you want
to heat or ventilate the vehicle interior
when the ignition is switched off. The
"residual heat" function can only be
activated or deactivated with the ignition
switched off.Overview of climate control systems131Climate controlZ

Control panel for 3-zone automatic climate control
Canada only
Front control panel:To set the temperature, left (Y page 137);To set climate control to automatic ( Y page 136)=To direct the airflow through the defroster vents, left ( Y page 138)?To defrost the windshield ( Y page 138)ATo increase the airflow ( Y page 138)BTo switch the rear window defroster on/off ( Y page 139)CTo direct the airflow through the defroster vents, right ( Y page 138)DTo operate the rear-compartment climate control via the front control panel
( Y page 134)ETo set the temperature, right ( Y page 137)FTo switch climate control on/off ( Y page 134)GTo direct the airflow to the footwells and side air vents, right ( Y page 138)HTo direct the airflow through the center and side air vents, right ( Y page 138)ITo activate/deactivate cooling with air dehumidification ( Y page 135)To activate/deactivate the residual heat function ( Y page 140)JDisplayKTo reduce the airflow ( Y page 138)LTo activate/deactivate air-recirculation mode ( Y page 140)MTo direct the airflow through the center and side air vents, left ( Y page 138)NTo direct the airflow to the footwells and side air vents, left ( Y page 138)OInterior temperature sensor132Overview of climate control systemsClimate control

PTo switch the MONO function on/off (Y page 138) Rear control panelQTo increase the airflow ( Y page 138)RTo set the temperature ( Y page 137)STo set the rear-compartment climate control to automatic ( Y page 136)TTo direct the airflow through the rear air vents ( Y page 138)UTo direct the airflow through the footwell vents( Y page 138)VTo switch rear-compartment climate control on/off ( Y page 134)WTo reduce the airflow ( Y page 138)
USA only
Front control panel:To set the temperature, left ( Y page 137);To set climate control to automatic ( Y page 136)=To defrost the windshield ( Y page 138)?To increase the airflow ( Y page 138)ATo direct the airflow through the defroster vents ( Y page 138)BTo activate/deactivate cooling with air dehumidification ( Y page 135)To activate/deactivate the residual heat function ( Y page 140)CTo set the temperature, right ( Y page 137)DTo switch rear-compartment climate control on/off ( Y page 134)ETo direct the airflow through the center and side air vents ( Y page 138)FTo direct the airflow to the footwells and side air vents ( Y page 138)GTo display the airflow levelOverview of climate control systems133Climate controlZ

HTo reduce the airflow (Y page 138)ITo switch the rear window defroster on/off ( Y page 139)JTo activate/deactivate air-recirculation mode ( Y page 140)KInterior temperature sensorLTo switch climate control on/off ( Y page 134) Rear control panelMTo increase the airflow ( Y page 138)NTo set the temperature ( Y page 137)OTo set the rear-compartment climate control to automatic ( Y page 136)PTo direct the airflow through the rear air vents ( Y page 138)QTo direct the airflow through the footwell vents ( Y page 138)RTo switch rear-compartment climate control on/off ( Y page 134)STo reduce the airflow ( Y page 138)Notes on using 3-zone automatic
climate control
The following contains instructions and
recommendations to enable you to get the
most out of your automatic climate control.
R Activate climate control using the à and
Á buttons. The indicator lamps in the
à and Á buttons light up.
R Set the temperature to 72 ‡ (22 †).
R Only use the "defrosting" function briefly
until the windshield is clear again.
R Only use "air-recirculation" mode briefly,
e.g. if there are unpleasant outside odors
or when in a tunnel. The windows could
otherwise fog up as, in air-recirculation
mode, no fresh air is drawn into the vehicle.
R Use the MONO function if you want to
adopt the temperature and air distribution
settings from the driver's side for all
climate zones. The indicator lamp in the
º button lights up.
R Use the residual heat function if you want
to heat or ventilate the vehicle interior
when the ignition is switched off. The
"residual heat" function can only be
activated or deactivated with the ignition
switched off.Operating the climate control system
Activating/deactivating climate
control
Important information
GWARNING
When the climate control system is
deactivated, the outside air supply and
circulation are also deactivated. Only choose
this setting for a short time. Otherwise the
windows could fog up, impairing visibility and
endangering you and others.
i Switch on climate control primarily using
the à button ( Y page 136).
134Operating the climate control systemClimate control

Switching the front climate control on/
off using the front control panelXTurn the SmartKey to position 2 in the
ignition lock.XTo switch on: press the à button.
The indicator lamp in the à button lights
up. Airflow and air distribution are set to
automatic mode.
or
XPress the ^ button.
The indicator lamp in the ^ button goes
out. The previously selected settings come
into effect again.XTo switch off: press the ^ button.
The indicator lamp in the ^ button lights
up.
Switching the rear-compartment
climate control on/off using the front
control panel
2-zone automatic climate control
XTurn the SmartKey to position 2 in the
ignition lock.XTo switch on/off: press the ± button.
The indicator lamp in the ± button lights
up or goes out.
3-zone automatic climate control
USA only:
XTurn the SmartKey to position 2 in the
ignition lock.XTo switch on/off: press the ± button.
The indicator lamp in the ± button lights
up or goes out.
Canada only:
XTurn the SmartKey to position 2 in the
ignition lock.XTo switch on: press the Y button.
ON and MODE are shown in the automatic
climate control display behind the Y
symbol. The MODE display goes out after
three seconds. The display switches back
to the standard display.XTo switch off: press the Y button.
MODE is shown in the display behind the
Y symbol.XPress button ^.
OFF is shown in the display behind the
Y symbol.
Switching the rear-compartment
climate control on/off using the rear
control panel
3-zone automatic climate control
XTurn the SmartKey to position 2 in the
ignition lock.XSwitch on automatic climate control using
the front control panel.XTo switch on: press the à button.
The indicator lamp in the à button lights
up.XTo switch off: press the ^ button.
The indicator lamp in the ^ button lights
up.
Activating/deactivating the cooling
with air dehumidification function
Important information
The cooling with air dehumidification function
is only available when the engine is running.
The air inside the vehicle is cooled and
dehumidified according to the temperature
selected.
GWARNING
If you switch off the cooling function, the
vehicle will not be cooled when weather
conditions are warm. The windows can fog up
more quickly. Window fogging may impair
visibility and endanger you and others.
Condensation may drip from the underside of
the vehicle when it is in cooling mode. This is
normal and not a sign that there is a
malfunction.
Operating the climate control system135Climate controlZ

iThe cooling with air dehumidification
function uses refrigerant R134a. This
coolant does not contain
chlorofluorocarbons, and therefore does
not damage the ozone layer.
Activating/deactivating
! If the cooling with air dehumidification
does not switch on, it is possible that the
climate control system has lost coolant.
Have the cooling with air dehumidification
checked at a qualified specialist workshop.
XTo activate: press the Á button.
The indicator lamp in the Á button lights
up.XTo switch off: press the Á button.
The indicator lamp in the Á button goes
out. The cooling with air dehumidification
function has a delayed switch-off feature.
Problems with the cooling with air
dehumidification function
If the indicator lamp in the Á button does
not go out when the function is activated, the
cooling with air dehumidification function is
deactivated due to a malfunction. You can no
longer switch on the cooling with air
dehumidification function.
XConsult a qualified specialist workshop.
Setting climate control to automatic
GWARNING
If you switch off the cooling function, the
vehicle will not be cooled when weather
conditions are warm. The windows can fog up
more quickly. Window fogging may impair
visibility and endanger you and others.
In automatic mode, the set temperature is
maintained automatically at a constant level.
The system automatically regulates the
temperature of the dispensed air, the airflow
and the air distribution.
Automatic mode will achieve optimal
operation if cooling with air dehumidification
is also activated. If desired, cooling with air
dehumidification can be deactivated.
Controlling the front climate control
using the front control panelXTurn the SmartKey to position 2 in the
ignition lock.XSet the desired temperature.XTo activate: press the à button.
The indicator lamp in the à button lights
up. Automatic air distribution and airflow
are activated.XTo deactivate: press the K or I
button.
The indicator lamp in the à button goes
out. Automatic airflow is deactivated and
the airflow is controlled according to the
level set. Automatic air distribution
remains activated.
or
XPress the Z, M , ¯ , \ , P ,
c or O button.
The indicator lamp in the à button goes
out. Automatic air distribution is
deactivated. Air distribution is controlled
according to the position set. Automatic
airflow remains activated.
Controlling the rear-compartment
climate control automatically using the
rear control panel
XTurn the SmartKey to position 2 in the
ignition lock.XSwitch on automatic climate control using
the front control panel.XSet the desired temperature.XTo activate: press the à button.
The indicator lamp in the à button lights
up. Automatic air distribution and airflow
are activated.136Operating the climate control systemClimate control

XTo deactivate: press the K or I
button.
Automatic airflow is deactivated and the
airflow is controlled according to the level
set. Automatic air distribution remains
activated.
or
XPress one of the M or O buttons.
Automatic air distribution is deactivated.
Air distribution is controlled according to
the position set. Automatic airflow remains
activated.
Setting the temperature
2-zone automatic climate control
Different temperatures can be set for the
driver's and front-passenger sides.
XTurn the SmartKey to position 2 in the
ignition lock.XTo increase/reduce: turn controls : and
C clockwise or counter-clockwise
( Y page 131).
Only change the temperature setting in
small increments. Start at 72 ‡ (22 †).
3-zone automatic climate control
Automatic climate control climate zones
You can select different temperature settings
for the driver's and front-passenger sides as
well as for the rear compartment.
XTo increase/reduce the front-
compartment temperature using the
front control unit: turn the SmartKey in
the ignition lock to position 2.XTurn controls : and C15
/E 16
clockwise
or counter-clockwise ( Y page 132).
Only change the temperature setting in
small increments. Start at 72 ‡ (22 †).
USA only:
XTo increase/reduce the rear-
compartment temperature using the
front control unit: turn the SmartKey in
the ignition lock to position 2.XPress the ± button.XTurn control C clockwise or counter-
clockwise ( Y page 132).
Only change the temperature setting in
small increments. Start at 72 ‡ (22 †).
Canada only:
XTo increase/reduce the rear-
compartment temperature using the
front control unit: turn the SmartKey in
the ignition lock to position 2.XPress the Y button.
The display changes to rear-compartment
climate control.XTurn control E clockwise or counter-
clockwise ( Y page 132).
Only change the temperature setting in
small increments. Start at 72 ‡ (22 †).
i To return to the standard display, press
the Y button.
i The rear display changes to the standard
display automatically after three seconds.
XTo increase/reduce the temperature in
the rear compartment using the rear
control panel: turn the SmartKey in the
ignition lock to position 2.XTurn control N15
/R 16
clockwise or
counter-clockwise ( Y page 132).15
USA only.
16 Canada only.Operating the climate control system137Climate controlZ

Only change the temperature setting in
small increments. Start at 72 ‡ (22 †).
Setting the air distribution
Air distribution settings
Automatic climate control: the air distribution
can be set individually for the driver's and
front-passenger sides. 17
Front control unit:
ZDirects the airflow through the
defroster ventsMDirects the airflow through the
defroster vents¯Directs the airflow through the
defroster ventscDirects the airflow through the
footwell and side air ventsODirects the airflow through the
footwell and side air vents\Directs the airflow through the center
and side air ventsPDirects the airflow through the center
and side air vents
Rear control panel:
MDirects the airflow through the rear-
compartment air ventsODirects the airflow through the
footwell air vents
Adjusting
XTurn the SmartKey to position 2 in the
ignition lock.XPress the Z, M , ¯ , c , O ,
\ or P button.Setting the airflowXTurn the SmartKey to position 2 in the
ignition lock.XTo increase/reduce: press the K or
I button.
Vehicles with Voice Control System: when the
Voice Control System is switched on, the
airflow is restricted to 50%. When command
input is complete, the airflow is adjusted back
to the previous setting.
Activating/deactivating the MONO
function
The MONO function is only available with
automatic climate control. 18
You can use the MONO function to adopt the
settings configured for temperature, air
distribution and airflow on the driver's side for
the front-passenger side and the rear
compartment.
XPress the º button.
The indicator lamp in the º button lights
up or goes out.
Defrosting the windshield
You can use this function to defrost the
windshield or to defrost the inside of the
windshield and the side windows.
i You should only select the defrosting
function until the windshield is clear again.
XTurn the SmartKey to position 2 in the
ignition lock.XTo activate: press the ¦ button.
The indicator lamp in the ¦ button lights
up.17 Canada only.
18 Canada only.138Operating the climate control systemClimate control