2012 MERCEDES-BENZ B-CLASS fog light

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
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If you back up after activation, the steering
wheel is moved to the straight-ahead
position.
X Drive forwards or back up the vehicle, being
ready to brake at all times.
X Stop as soon as PARKTRONIC sounds the
continuous warning tone, if not before.
X Drive forwards and reverse as prompted by
the PARKTRONIC warning
displays, several
times if necessary.
Once you have exited the parking space
completely, the steering wheel is moved to
the straight-ahead position. You hear a tone
and the Park Assist Finished message
appears in the

multifunction display. You will
then have to steer and merge into traffic on
your own. PARKTRONIC is still available.
Canceling Active Parking Assist You can cancel Active Parking Assist at any
time.
X
Stop the movement of the multifunction
steering wheel or steer yourself.
Active Parking Assist will be canceled at
once. The Park Assist Canceled
message appears in the multifunction
display.
or
X Press the PARKTRONIC button on the
center console (
Y

page 171).
PARKTRONIC is switched off and Active
Parking Assist is immediately canceled.
The Park Assist Canceled message
appears in the multifunction display.
Active Parking Assist is canceled
automatically if:
R you engage the electric parking brake.
R parking using Active Parking Assist is no
longer possible.
R you are driving faster than 6 mph
(10 km/h).
R a wheel

spins, ESP®
intervenes or fails. The
÷ warning lamp lights up in the
instrument cluster. A warning tone sounds. The parking space
symbol disappears and the multifunction
display shows the
Park Assist Canceled
message.
If Active
Parking

Assist is canceled, you must
steer again yourself.
If a system malfunction occurs, the vehicle is
braked to a standstill. To drive on, depress the
accelerator again. Rear view camera
Important safety notes The rear view camera is only an aid. It is not
a replacement for your attention to your
immediate surroundings. You are always
responsible for safe maneuvering and
parking.
When
maneuvering

or parking, make
sure that there are no persons, animals or
objects in the area in which you are
maneuvering.
Under the following circumstances, the rear
view camera will not function, or will function
in a limited manner:
R the tailgate is open
R in heavy rain, snow or fog
R at night or in very dark places
R if the camera is exposed to very bright light
R if the area is lit by fluorescent light or LED
lighting (the display may flicker)
R if there is a sudden change in temperature,
e.g. when driving into a heated garage in
winter
R if the camera lens is dirty or obstructed
R if the rear of your vehicle is damaged. In
this event, have the camera position and
setting checked at a qualified specialist
workshop.176
Driving systemsDriving and parking
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monitored area. If you then switch on the
corresponding turn signal to change lanes,
you will also receive a visual and audible
collision warning.
For
this purpose, Blind Spot
Assist uses sensors in the rear bumper.
For Blind Spot Assist to assist you when
driving, the radar sensor system must be:
R activated(Y page 199)
R operational
Monitoring range of the sensors
In particular, the detection of obstacles can
be impaired if:
R dirt on the sensors or anything else
covering the sensors
R there is poor visibility, e.g. due to fog, heavy
rain or snow
R a narrow vehicle traveling in front, e.g. a
motorbike or bicycle
R the road has very wide lanes
R the road has narrow lanes
R you are not driving in the middle of the lane
R there are barriers or similar lane borders
Vehicles in the monitoring range are then not
indicated. Blind Spot Assist monitors the area up to
10 ft (
3.0 m

) behind your vehicle and directly
next to your vehicle, as shown in the diagram. For this purpose, Blind Spot Assist uses radar
sensors in the rear bumper.
If the
lanes

are narrow, vehicles driving in the
lane beyond the lane next to your vehicle may
be indicated, especially if the vehicles are not
driving in the middle of their lane. This may
be the case if the vehicles are driving on the
inner side of their lane.
Due to the nature of the system:
R warnings may be issued in error when
driving close to crash barriers or similar
solid lane borders.
R warnings may be interrupted when driving
alongside particularly long vehicles, e.g.
trucks, for a prolonged time.
The two sensors for Blind Spot Assist are
integrated into the sides of the rear bumper.
Make sure that the bumper is free of dirt, ice
or slush in the vicinity of the sensors. For
example, the radar sensors must not be
covered by bicycle racks or overhanging
loads. Following a severe impact or in the
event of damage to the bumpers, have the
function of the radar sensors checked at a
qualified specialist workshop. Blind Spot
Assist may otherwise not work properly.
Indicator and warning display
Blind Spot Assist is not active at speeds below
approximately 20 mph (30 km/h). Vehicles in
the monitoring range are then not indicated. :
Yellow indicator lamp/red warning lamp
When Blind Spot Assist is activated, indicator
lamp : in the exterior mirrors lights up
yellow at speeds

of up to 20 mph (30 km/h).182
Driving systems
Driving and parking
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Keeping Assist is merely an aid. You are
responsible for the distance to the vehicle in
front, for vehicle speed, for braking in good
time and for staying in your lane.
The Lane Keeping Assist does not keep the
vehicle in the lane.
The system may be impaired or may not
function if:
R
there is poor visibility, e.g. due to
insufficient illumination of
the road, or due
to snow, rain, fog or spray
R there is glare, e.g. from oncoming traffic,
the sun or reflections (e.g. when the road
surface is wet)
R the windshield is dirty, fogged up, damaged
or covered, for instance by a sticker, in the
vicinity of the camera
R there are no, several or unclear lane
markings for a lane, e.g. in areas with road
construction work
R the lane markings are worn away, dark or
covered up, e.g. by dirt or snow
R the distance to the vehicle in front is too
small and the lane markings thus cannot be
detected
R the lane markings change quickly, e.g.
lanes branch off, cross one another or
merge
R the road is narrow and winding
R there are strong shadows cast on the lane
A warning may be given if a front wheel
passes over a lane marking. It will warn you
by means of intermittent vibration in the
steering wheel for up to 1.5 seconds.
Switching on Lane Keeping Assist X
Switch on Active Lane Keeping Assist using
the on-board computer; to do so, select
Standard or Adaptive (Y page 195).
Symbol : appears in the multifunction
display.
If you drive at speeds above 40 mph
(60 km/h
) and lane markings are detected,
symbol : is highlighted. Lane Keeping
Assist is ready for use.
When Standard is selected, no warning
vibration occurs if:
R you switch on

the turn signals. In this event,
the warnings are suppressed for a certain
period of time.
R a driving safety system intervenes, such as
ABS, BAS or ESP ®
.
When Adaptive is selected, no warning
vibration occurs if:
R you switch on the turn signals. In this event,
the warnings are suppressed for a certain
period of time.
R a driving safety system intervenes, e.g.
ABS, BAS or ESP ®
.
R you accelerate hard, e.g. kickdown.
R you brake hard.
R you steer actively, e.g. swerve to avoid an
obstacle or change lanes quickly.
R you cut the corner on a sharp bend.
In order that you are warned only when
necessary and in good time if you cross the
lane marking, the system recognizes certain
conditions and warns you accordingly.
The warning vibration occurs earlier if:
R you approach the outer lane marking on a
bend.
R the road has very wide lanes, e.g. a
freeway.
R the system recognizes solid lane markings.
The warning vibration occurs later if:
R the road has narrow lanes.
R you cut the corner on a bend.184
Driving systems
Driving and parking
ProCarManuals.com

Activating/deactivating surround
lighting and exterior lighting delayed
switch-off
If you have activated the
Locator
Lighting: function
and
the light switch is set
to Ã, the following functions are activated
when it is dark:
R surround lighting: the exterior lighting
remains lit for 40 seconds after unlocking
with the SmartKey. If you start the engine,
the surround lighting is switched off and
automatic headlamp mode is activated
(Y page 99).
R exterior lighting delayed switch-off: the
exterior lighting remains lit for
60 seconds after the engine is switched off.
If you close all the doors and the trunk lid,
the exterior lighting goes off after
15 seconds.
X Press the = or ; button on the
steering wheel to select the Sett. menu.
X Press the :
or 9
button to select the
Lights submenu.
X Press a to confirm.
X Press the : or 9
button to select the
Locator Lighting function.
You will see the selected setting: Enabled
or Disabled.
X Press the a button to save the setting.
Deactivating delayed switch-off of the
exterior lighting temporarily:
X Before leaving the vehicle, turn the
SmartKey to position 0

in the ignition lock.
X Turn the SmartKey to position 2 in the
ignition lock.
The exterior lighting delayed switch-off is
deactivated.
Delayed switch-off of the exterior lighting is
reactivated the next time you start the
engine.
i Depending on your vehicle's equipment,
when the surround lighting and delayed
switch-off exterior lighting are on, the
following light up: R
Parking lamps
R Front fog lamps
R Low-beam headlamps
R Daytime running lamps
R Side marker lamps
R Surround lighting in the exterior mirrors
Activating/deactivating the interior
lighting delayed switch-off
If you activate the Interior Lighting
Delay function, the interior lighting remains
on for 20seconds after you remove the
SmartKey from the ignition lock.
X Press the = or ; button on the
steering wheel to select the Sett. menu.
X Press the : or 9
button to select the
Lights submenu.
X Press a to confirm.
X Press the :
or 9

button to select the
Interior Lighting Delay function.
You will see the selected setting: Enabled
or Disabled.
X Press the a button to save the setting.
Vehicle Activating/deactivating the automatic
door locking mechanism
X
Press the = or ; button on the
steering wheel to select the Sett menu.
X Press the :
or 9
button to select the
Vehicle submenu.
X Press a to confirm.
X Press the :
or 9

button to select the
Automatic Door Lock function.
You will see the selected setting: Enabled
or Disabled.
X Press the a button to save the setting.
If you select the Automatic Door Lock
function, the
vehicle

is centrally locked above
a speed of around 9 mph (15 km/h).
i For further information on the automatic
locking feature, see ( Y page 74).198
Menus and submenus
On-board computer and displays
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Display messages Possible causes/consequences and
M Solutionsb
Switch Off Lights The lights are still switched on when you leave the vehicle. A
warning tone also sounds.
X
Turn the light switch to Ã. Adaptive Highbeam
Assist Inoperative Adaptive Highbeam Assist is faulty.
X
Visit a qualified specialist workshop. Adaptive Highbeam
Assist Currently
Unavailable See
Operator's Manual Adaptive Highbeam Assist is deactivated and temporarily
inoperative. Possible causes are:
R
the windshield in the camera's field of vision is dirty.
R visibility is impaired due to heavy rain, snow or fog.
X Clean the windshield.
If the system detects that the camera is fully operational again,
the Adaptive Highbeam Assist Now Available message is
displayed.
Adaptive Highbeam Assist is operational again. Engine
Display messages Possible causes/consequences and
M Solutions+
Check Coolant
Level See
Operator's Manual The coolant level is too low.
!
Avoid making long
journeys with too little coolant in the engine
cooling system. The engine will otherwise be damaged.
X Add coolant, observing the warning notes before doing so
(Y page 269).
X If coolant needs to be added more often than usual, have the
engine coolant system checked at a qualified specialist
workshop. ? The fan motor is faulty.
X
At coolant temperatures below 248 ‡ (120 †), drive to the
nearest qualified specialist workshop.
X Avoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-and-go traffic.212
Display messages
On-board computer and displays
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