2012 MERCEDES-BENZ B-CLASS engine

The blue
K indicator lamp in the
instrument cluster lights
up when the high-
beam headlamps are switched on.
X To switch off the high-beam
headlamps: move the combination

switch
back to its normal position.
The blue K indicator lamp in the
instrument cluster goes out.
i Vehicles with Adaptive Highbeam Assist:
when Adaptive Highbeam Assist is active,
it controls activation of the high-beam
headlamps (Y page 102).
High-beam flasher X
To switch on: turn the SmartKey in the
ignition lock to position 1 or 2 or start the
engine.
X Pull the combination switch in the direction
of arrow =. Hazard warning lamps
The hazard warning lamps automatically
switch on if:
R
an air bag is deployed
R the vehicle decelerates rapidly from a
speed of
more

than 45mph (70 km/h) and
comes to a standstill
X To switch on the hazard warning lamps:
press button :.
All turn signals flash. If you now switch on
a turn signal

using the combination switch, only the turn signal lamp on the
corresponding side
of

the vehicle will flash.
X To switch off the hazard warning
lamps: press button :.
The hazard warning lamps switch off
automatically if the vehicle reaches a speed
of over 6mph (10km/h) again after a full
brake application.
i The hazard warning lamps still operate if
the ignition is switched off. Headlamp cleaning system
The headlamps are cleaned automatically if
the "Wipe with washer fluid" function is
operated five times

while the lights are on and
the engine is running (Y page 111). When you
switch off the ignition, the automatic
headlamp cleaning system is reset and
counting is resumed from 0. Cornering light function
The cornering light function improves the
illumination of the road over a wide angle in
the direction
you

are turning, enabling better
visibility in tight bends, for example. The
cornering light function can only be activated
when the low-beam headlamps are switched
on. Exterior lighting
101
Lights and windshield wipers Z
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If your vehicle is equipped with Xenon bulbs,
you can recognize this by the following: the
cone of light from the Xenon bulbs moves
from the top to the bottom and back again
when you start the engine. For this to be
observed, the lights must be switched on
before starting the engine.
Bulbs and lamps are an important aspect of
vehicle safety.
You
must therefore make sure
that these function correctly at all times.
Have the headlamp setting checked regularly.
Other bulbs G
WARNING
Bulbs, lamps and connectors can get very hot
when operating. If you change a bulb, you
could burn yourself on these components.
There is a risk of injury.
Allow these components

to cool down before
changing a bulb.
There are bulbs other than the Xenon bulbs
that you cannot replace. Replace only the
bulbs listed (Y page 105). Have the bulbs that
you cannot replace yourself changed at a
qualified specialist workshop.
If you require assistance changing bulbs,
consult a qualified specialist workshop.
Do not touch the glass tube of new bulbs with
your bare hands. Even minor contamination
can burn into the glass surface and reduce
the service life of the bulbs. Always use a lint-
free cloth or only touch the base of the bulb
when installing.
Only use bulbs of the correct type.
If the new bulb still does not light up, consult
a qualified specialist workshop.
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure
that these function correctly at all times.
Have the headlamp setting checked regularly. Overview: changing bulbs/bulb types
You can change

the following bulbs. The bulb
type can be found in the legend. Halogen headlamps
:
Turn signal lamp:3457
; High-beam headlamp: H7 55 W
= Parking lamp/standing lamp: W 5 W LL
? Low-beam headlamp: H7 55 W Vehicles with Intelligent Light System
:
Cornering lamp: H7 55 W Replacing bulbs
105
Lights and windshield wipers Z
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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 Read the information on qualified
specialist workshops: ( Y page 24).Overview of climate control systems
Important safety notes
Observe the settings recommended on the
following pages. The windows could
otherwise fog up.
To prevent the windows from fogging up:
R switch off climate control only briefly
R switch on air-recirculation mode only
briefly
R switch on the cooling with air
dehumidification function
R switch on the defrost windshield function
briefly, if required
The automatic climate control regulates the
temperature and the humidity of the vehicle
interior and filters out undesirable
substances from the air.
Automatic climate control/dual-zone
automatic climate control is only operational
when the engine is running. Optimum
operation is only achieved with the side
windows and panorama

roof with power tilt/
sliding panel closed.
The residual heat function can only be
activated or deactivated with the ignition
switched off (Y page 129).
i Ventilate the vehicle for a brief period
during warm weather, e.g. using the
convenience opening feature ( Y page 78).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 Maintenance Booklet. As it
depends on environmental conditions, e.g.
heavy air pollution, the interval may be
shorter than stated in the Maintenance
Booklet.
i It is possible that the dehumidification
function of the climate control system may
be activated automatically an hour after the
SmartKey has been removed. The vehicle
is then ventilated for 30 minutes. 118
Overview of climate control systems
Climate control
ProCarManuals.com

?
To activate/deactivate air-recirculation mode ( Y page 129)
A To set the airflow ( Y page 126)
B To switch cooling with air dehumidification on/off ( Y page 123)
C To switch the rear window defroster on/off (Y page 128) Notes on using automatic climate
control
Automatic climate control The following contains notes and
recommendations on optimum use of the
automatic climate control.
R
Switch on the air-conditioning system by
turning control knob A clockwise to the
desired position (except position 0).
R Set the temperature to 72 ‡ (22 †).
R Recommendation for preventing
fogged up windows with low outside
temperatures
or rain: switch ¯ on for
the air distribution and switch P and
O off if possible (Y page 126).
In air-recirculation mode, switch d off
(Y page 129).
Set airflow control A to a setting between
3 and 6(Y page 126).
R Recommendation for rapid cooling or
heating of the vehicle interior: briefly set
airflow control A to a setting between 3
and 6(Y page 126).
R Recommendation for a constant
vehicle interior temperature: set airflow
control A to a setting between 1 and
3(Y page 126).
R Recommendation for air distribution in
the winter: set O and
¯(Y page 126).
Recommendation for air distribution in
the summer: set P or P and
¯(Y page 126).
R Only use the "windshield 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, since no fresh air is drawn
into the vehicle in air-recirculation mode.
R If you change the settings of the climate
control system, the climate status display
appears for three seconds at the bottom of
the screen in the COMAND display. See
also the separate COMAND operating
instructions 4
. You will see the current
settings of the various climate control
functions.
ECO start/stop function During automatic engine switch-off, the ECO
start/stop function only operates at a
reduced capacity. If you require the full
climate control
output,

you can switch off the
ECO start/stop function by pressing the ECO
button ( Y page 138).
4 Only for vehicles with "COMAND Multimedia System" optional equipment120
Overview of climate control systemsClimate control
ProCarManuals.com

for the front-passenger side as well. The
indicator lamp
in
the á button goes out.
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.
ECO start/stop function During automatic engine switch-off, the ECO
start/stop function only operates at a
reduced capacity. If you require the full
climate control
output,

you can switch off the
ECO start/stop function by pressing the ECO
button ( Y page 138). Operating the climate control
systems
Switching climate control on/off
Points to observe before use When the climate control is switched off, the
air supply and air circulation are also
switched off. The windows could fog up.
Therefore, switch off climate control only
briefly
Activating/deactivating
Automatic climate control
X
Turn the SmartKey to position 2 in the
ignition lock (Y page 135).
X To switch on: turn control A
clockwise to
the desired position (except position 0)
(Y page 119).
X To switch off: turn control A counter-
clockwise to position 0(Y page 119). Dual-zone automatic climate control
X
Turn the SmartKey to position 2 in the
ignition lock (Y page 135).
X To activate: press the à button.
The indicator
lamp

in the à button lights
up. Airflow and air distribution are set to
automatic mode.
or
X Press the ^ button.
The indicator lamp

in the ^ button goes
out. The previously selected settings are
restored.
X To deactivate: press the ^ button.
The indicator lamp

in the ^ button lights
up.
i Dual-zone automatic climate control:
switch on climate control primarily using
the à button. Activating/deactivating cooling with
air dehumidification
Points to observe before use If you deactivate the "Cooling with air-
dehumidification" function, the air inside the
vehicle will not be cooled. The air inside the
vehicle will also not be dehumidified. The
windows can
fog

up more quickly. Therefore,
only deactivate the "Cooling with air-
dehumidification" function briefly.
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.
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 systems
123
Climate control
ProCarManuals.com

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 "windshield
defrosting" function until the windshield is
clear again.
X Turn the SmartKey to position 2 in the
ignition lock (Y page 135).
X To activate: press the ¬ button.
The indicator lamp
in the ¬ button lights
up.
The climate control system switches to the
following functions:
R high airflow
R high temperature
R air distribution to the windshield and
front side windows
R air-recirculation mode off
i The "windshield defrosting" function
automatically sets the

blower output to the
optimum defrosting effect. As a result, the
airflow may increase or decrease
automatically after the button is pressed.
i You can adjust the blower output
manually while the "Windshield defrosting"
function is in operation:
R Automatic climate control: turn airflow
control A clockwise or counter-
clockwise (Y page 119).
R Dual-zone automatic climate control:
press the ó or ô button.
X To deactivate: press the ¬ button.
The indicator lamp

in the ¬ button goes
out. The previously selected settings are
restored. Air-recirculation mode remains
deactivated.
or X
Press the à button. 5
The indicator
lamp

in the ¬ button goes
out. Airflow and air distribution are set to
automatic mode.
or
X Automatic climate control: turn
temperature control : clockwise or
counter-clockwise ( Y page 119).
Dual-zone automatic climate control:
turn temperature controls : or E
clockwise or counter-clockwise
(Y page 121). MAX COOL maximum cooling
The MAX COOL function is only available in
vehicles for the USA.
MAX COOL is only operational when the
engine is running.
X To activate: press the Ù button.
The indicator lamp in the button lights up.
X To deactivate: press the Ù button
again.
The indicator lamp

goes out. The previously
selected settings are restored.
When you activate MAX COOL, climate
control switches to the following functions:
R maximum cooling
R maximum airflow
R air-recirculation mode on Defrosting the windows
Windows fogged up on the inside Automatic climate control
X
Activate the ¿ "Cooling with air
dehumidification" function.
X If the windows continue to fog up, activate
the "windshield defrosting" function
(Y page 127).
5 3-zone automatic climate control only. Operating the climate control systems
127Climate control
ProCarManuals.com

Problems with the rear window defroster
Problem Possible causes/consequences and
M SolutionsThe rear window
defroster has
deactivated
prematurely or cannot
be activated. The battery has not been sufficiently charged.
X
Switch off any consumers that are not required, e.g. reading
lamps, interior lighting or the seat heating.
When the battery is sufficiently charged, the rear window
defroster can be activated again. Activating/deactivating air-
recirculation mode
If you switch on air-recirculation mode, the
windows can fog up more quickly, in
particular at low temperatures. Only use air-
recirculation mode briefly to prevent the
windows from fogging up.
You can deactivate the flow of fresh air if
unpleasant odors are entering the vehicle
from outside. The air already inside the
vehicle will then be recirculated.
The operation of
air-recirculation mode is the
same for all control panels.
X Turn the SmartKey to position 2 in the
ignition lock (Y page 135).
X To activate: press the e button.
The indicator lamp

in the e button lights
up.
i Air-recirculation mode is activated
automatically at high outside
temperatures. When air-recirculation

mode
is activated automatically, the indicator
lamp in the e button is not lit.
Outside air is added after about
30 minutes.
X To deactivate: press the e button.
The indicator lamp

in the e button goes
out. i
Air-recirculation mode deactivates
automatically:
R after approximately five minutes at
outside temperatures below
approximately 41 ‡ (5 †)
R after approximately five minutes if the
"Cooling with air dehumidification"
function is deactivated
R after approximately 30 minutes at
outside temperatures above
approximately

41 ‡(5 †) if the "Cooling
with air dehumidification" function is
activated Activating/deactivating the residual
heat function
The residual heat

function is only available in
vehicles for Canada with dual-zone automatic
climate control.
It is possible to make use of the residual heat
of the engine to continue heating the vehicle
for approximately 30 minutes after the engine
has been switched off. The heating time
depends on the temperature that has been
set.
i The blower will run at a low speed
regardless of the airflow setting.
i If you activate the residual heat function
at high temperatures, only the ventilation
will be activated. The blower runs at
medium speed. Operating the climate control systems
129
Climate control
ProCarManuals.com

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 Read the information on qualified
specialist workshops: ( Y page 24).Notes on breaking-in a new vehicle
Important safety notes
New and replaced brake pads and discs only
reach their optimum braking effect after
several hundred kilometers of driving.
Compensate for this

by applying greater force
to the brake pedal. The first 1,000miles (1,500 km)
The more you

look after the engine when it is
new, the more satisfied you will be with its
performance in the future.
R You should therefore drive at varying
vehicle and engine speeds for the first
1,000 miles (1,500 km).
R Avoid heavy loads, e.g. driving at full
throttle, during this period.
R Change gear in good time, before the
tachometer needle is Ô of the way to the
red area of the tachometer.
R Do not manually shift to a lower gear to
brake the vehicle.
R If possible, do not depress the accelerator
pedal past the point of resistance
(kickdown).
R Ideally, for the first 1,000 miles (1,500 km),
drive in program E. After 1,000 miles (1,500km), you can
increase the
engine

speed gradually and bring
the vehicle up to full speed.
i You should also observe these notes on
breaking-in if the engine or parts of the
drive train on your vehicle have been
replaced.
i Always observe the respective speed
limits. Driving
Important safety notes
G
WARNING
Objects in the driver's footwell can restrict the
pedal travel or obstruct a depressed pedal.
The operating and road safety of the vehicle
is jeopardized. There is a risk of an accident.
Make sure that all objects in the vehicle are
stowed correctly, and that they cannot enter
the driver's footwell. Install the floormats
securely and as specified in order to ensure
sufficient clearance for

the pedals. Do not use
loose floormats. G
WARNING
Unsuitable footwear can hinder correct usage
of the pedals, e.g.:
R shoes with thick soles
R shoes with high heels
R slippers
There is a risk of an accident.
Wear suitable footwear to ensure correct
usage of the pedals. G
WARNING
If you switch off the ignition while driving,
safety-relevant functions are only available
with limitations, or

not at all. This could affect,
for example, the power steering and the brake
boosting effect. You will require considerably
more effort to steer and brake. There is a risk
of an accident. 134
Driving
Driving and parking
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