key MERCEDES-BENZ B-CLASS 2012 Service Manual

Automatic headlamp mode
G
WARNING
When the light switch is set to Ã,
the low-
beam headlamps may not be switched on
automatically if there is fog, snow or other
causes of poor visibility due to the weather
conditions
such as spray. There is a risk of an
accident.
In such situations, turn the light switch to
L.
The automatic headlamp feature is only an
aid. The driver is responsible for the vehicle's
lighting at all times.
à is the favored light switch setting. The
light setting is automatically selected
according to the brightness of the ambient
light (exception: poor visibility due to weather
conditions such as fog, snow or spray):
R SmartKey in position 1 in the ignition lock:
the parking lamps are switched on or off
automatically depending on the brightness
of the ambient light.
R With the engine running: if you have
activated the daytime running lamps
function via the on-board computer, the
daytime running lamps or the low-beam
headlamps and parking lamps are switched
on or off automatically depending on the
brightness of the ambient light.
X To switch on automatic headlamp
mode: turn the light switch to Ã.
The daytime running lamps improve the
visibility of your vehicle during the day. The
daytime running lamps

function is required by
law in Canada.
When the engine is running and the vehicle is
stationary: if you move the selector lever from
a drive position to P, the daytime running
lamps/low-beam headlamps go out after
three minutes.
When the engine is running, the vehicle is
stationary and in high ambient light: if you
turn the light switch to T, you turn on the
daytime running lamps and parking lamps. If the engine is running and you turn the light
switch to L, the manual settings take
precedence over the daytime running lamps.
Low-beam headlamps
Even if the light sensor does not detect that
it is dark, the parking lamps and low-beam
headlamps switch on when the ignition is
switched
on and

the light switch is set to the
L position. This is a particularly useful
function in the event of rain and fog.
X To switch on the low-beam headlamps:
turn the SmartKey in the ignition lock to
position 2 or start the engine.
X Turn the light switch to L.
The green L indicator lamp in the
instrument cluster lights up.
Front fog lamps
In conditions where visibility is poor due to
fog, snow or rain, the fog lamps improve
visibility as well as making it easier for other
road users to see you. They can be operated
together with the parking lamps or together
with the parking lamps and low-beam
headlamps.
X To switch on the front fog lamps: turn
the SmartKey in

the ignition lock to position
2 or start the engine.
X Turn the light switch to L or Ã.
X Press the N button.
The green N indicator lamp in the
instrument cluster lights up.
X To switch off the front fog lamps: press
the N button.
The green N indicator lamp in the
instrument cluster goes out.
Only vehicles with front fog lamps are
equipped with the "fog lamp" function;
information on the fog lamp function for
vehicles with Intelligent Light System
(Y page 102). Exterior lighting
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Rear fog lamp
The rear fog lamp improves visibility of your
vehicle for the traffic behind in the event of
thick fog. Please take note of the country-
specific regulations for the use of rear fog
lamps.
X
To switch on the rear fog lamps: turn the
SmartKey in the ignition lock to position 2
or start the engine.
X Turn the light switch to
L or Ã.
X Press the R button.
The yellow R indicator lamp in the
instrument cluster lights up.
X To switch off the rear fog lamp: press the
R
button.
The yellow R indicator lamp in the
instrument cluster goes out.
Parking lamps
! If the battery has been excessively
discharged, the parking lamps or standing
lamps are automatically switched off to
enable the next engine start. Always park
your vehicle safely and sufficiently lit
according to legal standards. Avoid the
continuous use of the T parking lamps
for several hours.

If possible, switch on the
X right or the W left standing lamp.
X To switch on: turn the light switch to
T.
The green T indicator lamp in the
instrument cluster lights up.
Standing lamps
Switching on the

standing lamps ensures the
corresponding side of the vehicle is
illuminated.
X To switch on the standing lamps: the
SmartKey is not in the ignition lock or it is
in position 0.
X Turn the light switch to W (left-hand side
of the vehicle) or
X (right-hand side of
the vehicle). Combination switch
Turn signal :
High-beam headlamps
; Turn signal, right
= High-beam flasher
? Turn signal, left
X To indicate briefly: press the
combination
switch briefly to the pressure point in the
direction of arrow

; or ?.
The corresponding turn signal flashes three
times.
X To indicate: press the combination
switch
beyond the pressure point in the direction
of arrow ; or ?.
High-beam headlamps X
To switch on the high-beam headlamps:
turn the SmartKey in the ignition lock to
position 2 or start the engine.
X Turn the light switch to L or Ã.
X Press the combination switch beyond the
pressure point in the direction of
arrow :.
In the à position, the high-beam
headlamps are only switched on when it is
dark and the engine is running. 100
Exterior lighting
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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
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?
| To switch the front interior lighting/
automatic interior lighting control off
A p To switch the right-hand front
reading lamp on/off
B To switch the automatic interior lighting
control on Rear-compartment overhead control panel
:
To switch the reading lamp on/off Interior lighting control
Important notes In order to prevent the vehicle's battery from
discharging, the
interior
lighting functions are
automatically deactivated after some time
unless the SmartKey is in position 2 in the
ignition lock.
The brightness of the ambient lighting may be
set using the on-board computer
(Y page 197).
Automatic interior lighting control X
To switch on: set the switch to center
position B.
X To switch off: set the switch to the |
position.
The interior lighting automatically switches
on if you:
R unlock the vehicle
R open a door
R remove the SmartKey from the ignition
lock. The interior light is activated for a short while
when the SmartKey is removed from the
ignition lock. You can activate this delayed
switch-off using the on-board computer
(Y page 198).
Manual interior lighting control
X
To switch the front interior lighting on:
set the switch to the c position.
X To switch the interior lighting off: set the
switch to the |

position or (if the door
is closed) to the center position.
X To switch the interior lighting on/off:
press the u button.
X To switch the reading lamps on/off:
press the p button. Crash-responsive emergency lighting
The interior lighting

is activated automatically
if the vehicle is involved in an accident.
X To switch off the crash-responsive
emergency lighting: press the hazard
warning lamp button.
or
X Lock and then unlock the vehicle using the
key. Replacing bulbs
Important safety notes
Xenon bulbs G
DANGER
Xenon bulbs carry a high voltage. You can get
an electric shock if you remove the cover of
the Xenon bulb and touch the electrical
contacts. There is a risk of fatal injury.
Never touch the parts or the electrical
contacts of the

Xenon bulb. Always have work
on the Xenon bulbs carried out at a qualified
specialist workshop. 104
Replacing bulbs
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!
If the windshield wipers leave smears on
the windshield after the vehicle has been
washed in an automatic car wash, wax or
other residues may be the reason for this.
Clean the windshield using washer fluid
after washing the vehicle in an automatic
car wash. Combination switch
1
$ Windshield wiper off
2 Ä Intermittent wipe, low (rain sensor
set to low sensitivity)
3 Å Intermittent wipe, high (rain sensor
set to high sensitivity)
4 ° Continuous wipe, slow
5 ¯
Continuous wipe, fast
B í Single wipe/ î To wipe the
windshield using washer fluid
X Switch on the ignition.
X Turn the combination switch to the
corresponding position.
! Vehicles with a rain sensor: if the
windshield becomes dirty in dry weather
conditions, the windshield wipers may be
activated inadvertently. This could then
damage the windshield wiper blades or
scratch the windshield.
For this reason, you should always switch
off the windshield wipers in dry weather.
Vehicles with
a

rain sensor: in the Ä or
Å position, the appropriate wiping
frequency is automatically set according to
the intensity of the rain. In the Å position,
the rain sensor is more sensitive than in the Ä position, causing the windshield
wipers to wipe more frequently.
If the wiper blades are worn, the windshield
will no longer be wiped properly. This could
prevent you from observing the traffic
conditions. Replace the wiper blades twice a
year, ideally in spring and fall.
Switching the rear window wiper on/
off
Combination switch
:
è Switch
2 ô To wipe with washer fluid
3 I To switch on intermittent wiping
4 0 To switch off intermittent wiping
5 ô To wipe with washer fluid
X Turn the SmartKey to position 1 or
2
in the
ignition lock.
X Turn switch : on the combination switch
to the corresponding position.
When the rear

window wiper is switched on,
the icon appears in the instrument cluster. Replacing the wiper blades
Important safety notes G
WARNING
If the windshield wipers begin to move while
you are changing

the wiper blades, you could
be trapped by the wiper arm. There is a risk
of injury. 112
Windshield wipers
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Always switch off the windshield wipers and
ignition before changing the wiper blades.
! To avoid damaging the wiper blades,
make sure that you touch only the wiper
arm of the wiper.
! Never open the hood/tailgate if a wiper
arm has been folded away from the
windshield/rear window.
Never fold a windshield wiper arm without
a wiper blade back onto the windshield/
rear window.
Hold the windshield
wiper arm firmly when
you change the wiper blade. If you release
the wiper arm without a wiper blade and it
falls onto the windshield/rear window, the
windshield/rear window may be damaged
by the force of the impact.
Mercedes-Benz recommends that you have
the wiper blades changed at a qualified
specialist workshop.
Changing the windshield wiper blades Removing the wiper blades
X
Remove the SmartKey from the ignition
lock.
X Fold the wiper arm away from the
windshield. X
Press both release clips ;.
X Fold wiper blade : in the direction of
arrow = away from wiper arm ?.
X Remove wiper blade : in the direction of
arrow A. Installing the wiper blades
X
Position new wiper blade : with
recess B on lug A.
X Fold wiper blade : in the direction of
arrow = onto
the

wiper arm, until retaining
clips ; engage in bracket ?.
X Make sure that wiper blade : is seated
correctly.
X Fold the wiper arm back onto the
windshield.
Replacing the rear window wiper blade Removing a wiper blade
X
Remove the SmartKey from the ignition
lock.
X Fold wiper arm : away from the rear
window until it engages.
X Position wiper blade ; at a right angle to
wiper arm :. Windshield wipers
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Problems with the windshield wipers
Problem Possible causes/consequences and
M SolutionsThe windshield wipers
are jammed. Leaves or snow, for example, may be obstructing the windshield
wiper movement. The wiper motor has been deactivated.
X
For safety reasons, you should remove the SmartKey from the
ignition lock.
X Remove the cause of the obstruction.
X Switch the windshield wipers back on. The windshield wipers
fail completely. The windshield wiper drive is malfunctioning.
X
Select another wiper speed on the combination switch.
X Have the windshield wipers checked at a qualified specialist
workshop. The spray nozzles are
misaligned. The windshield washer fluid from the spray nozzles no longer hits
the center of the windshield. The spray nozzles are misaligned.
X
Have the spray nozzles adjusted at a qualified specialist
workshop. Windshield wipers
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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
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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
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Climate control
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Problems with the "Cooling with air dehumidification" function
Problem Possible causes/consequences and
M SolutionsThe indicator lamp in
the ¿ button
flashes three times or
remains off. The
"Cooling with air
dehumidification"
function cannot be
switched on. Cooling with air dehumidification has been deactivated due to a
malfunction.
X
Visit a qualified specialist workshop. Setting the climate control to
automatic
The automatic function is only available in
conjunction with dual-zone
automatic climate
control.
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.
The automatic mode functions optimally
when the "Cooling with air dehumidification"
function is activated. If necessary, cooling
with air dehumidification can be deactivated.
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.
X Turn the SmartKey to position 2 in the
ignition lock (Y page 135).
X Set the desired temperature.
X To activate: press the à button.
The indicator lamp

in the à button lights
up. Automatic air distribution and airflow
are activated. X
To switch to manual mode: press the
É or Ë button.
or
X Press the K or I button.
The indicator lamp

in the à button goes
out. Automatic air distribution and airflow
are deactivated. Setting the temperature
Automatic climate control You can set the temperature for the entire
vehicle.
X
Turn the SmartKey to position 2 in the
ignition lock (Y page 135).
X To increase/reduce: turn control :
clockwise or counter-clockwise
(Y page 119).

Only change the temperature
setting in small increments. Start at 72 ‡
(22 †).
Dual-zone automatic climate control Different temperatures can be set for the
driver's and front-passenger sides.
X
Turn the SmartKey to position 2 in the
ignition lock (Y page 135).
X To increase/reduce: turn control : or
E clockwise or counter-clockwise
(Y page
121).

Only change the temperature Operating the climate control systems
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Climate control
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