warning light MERCEDES-BENZ A-CLASS HATCHBACK 2012 Service Manual

Setting the exterior lighting
Setting options Exterior lighting can be set using the:
R light switch
R headlamp range control (vehicles with hal-
ogen headlamps only) (Y page 107)
R combination switch (Y page 107)
R on-board computer (Y page 221)
Light switch Operation
1W
Left-hand parking lamps
2X Right-hand parking lamps
3T Side lamps, licence plate and instru-
ment cluster lighting
4Ã Automatic headlamp mode, control-
led by the light sensor
5L Dipped-beam/main-beam head-
lamps
BR Rear foglamp
CN Foglamp (vehicles with front fog-
lamps only)
If you hear a warning tone when you leave the
vehicle, the lights may still be switched on.
X Turn the light switch to Ã.
The exterior lighting (except the side lamps/
parking lamps) switches off automatically if
you:
R remove the key from the ignition lock
R open the driver's door with the key in posi-
tion 0. Automatic headlamp mode G
WARNING
When the light switch is set to Ã, the
dipped-beam headlamps may not be switched on automatically if there is fog, snow or othercauses 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 preferred light switch setting. The
light setting is automatically selected accord-
ing to the brightness of the ambient light
(exception: poor visibility due to weather con- ditions such as fog, snow or spray):
R Key in position 1in the ignition lock: the
side lamps are switched on or off automat- ically depending on the brightness of the
ambient light.
R With the engine running: if you have
switched on the daytime driving lights func-
tion in the on-board computer, the daytime
driving lights or the side lamps and dipped- beam headlamps are switched on or off
automatically depending on the brightnessof the ambient light.
X To switch on automatic headlamp
mode: turn the light switch to Ã.
The daytime driving lights improve the detect- ability of your vehicle during the day. Here,
the daytime driving lights function must be
switched on via the on-board computer
(Y page 221).
When the dipped-beam headlamps are
switched on, the Lindicator lamp in the
instrument cluster lights up and the daytime
driving lights switch off.
Dipped-beam headlamps
When the ignition is switched on and the light switch is in position L, the side lamps and
dipped-beam headlamps are switched on Exterior lighting
105Lights and windscreen wipers Z

i
Vehicles with Adaptive Highbeam Assist:
when Adaptive Highbeam Assist is active, it controls activation of the main-beam head-lamps (Y page 109).
Headlamp flasher X
To switch on: turn the key in the ignition
lock to position 1or 2, or start the engine.
X Pull the combination switch in the direction
of arrow =. Hazard warning lamps
The hazard warning lamps switch on auto-
matically if:
R an airbag is deployed or
R the vehicle decelerates rapidly from a
speed of more than 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 corre-
sponding side of the vehicle will flash.
X To switch off the hazard warning lamps:
press button :.
The hazard warning lamps switch off auto-
matically if the vehicle reaches a speed of
over 10 km/h again after a full brake appli-
cation.
i The hazard warning lamps still operate if
the ignition is switched off. Headlamp cleaning system
If the "Wipe with washer fluid" function is
operated five times (Y page 116) while the
lights are on and the engine is running, the
headlamps are cleaned automatically. When
you switch off the ignition, the automatic
headlamp cleaning system is reset and count-
ing is resumed from 0. Intelligent Light System
General notes The Intelligent Light System is a system that
adjusts the headlamps automatically to suit
the prevailing driving and weather conditions.
It offers advanced functions for improved illu-
mination of the road surface, e.g. depending
on the vehicle speed or weather conditions.
The system includes the active light function, cornering light function, motorway mode and
extended range foglamps. The system is only active when it is dark.
You can activate or deactivate the "IntelligentLight System" using the on-board computer
(Y page 221).
Active light function The active light function is a system that
moves the headlamps according to the steer-
ing movements of the front wheels. In this
way, relevant areas remain illuminated while
driving. This allows you to recognise pedes-
trians, cyclists and animals.
Active: when the lights are switched on. 108
Exterior lightingLights and windscreen wipers

Cornering light function
The cornering light function improves the illu-
mination of the road over a wide angle in the
direction you are turning, enabling better vis- ibility in tight bends, for example. The corner-ing light function can only be activated when
the dipped-beam headlamps are switched on.
Active:
R if you are driving at speeds below 40 km/h
and the turn signal is activated or the steer- ing wheel is turned.
R if you are driving at speeds between
40 km/h and 70 km/h and turn the steer-
ing wheel.
Not active: if you are driving at speeds above
40 km/h or switch off the turn signal or turn
the steering wheel to the straight-ahead posi-
tion.
The cornering lamp may remain lit for a short
time, but is automatically switched off after
no more than three minutes.
Motorway mode Motorway mode increases the range of the
beam.
Active:
R if you are driving at speeds above
110 km/h and do not make any large steer-
ing movements for 1000 m
R if you are driving at speeds above
130 km/h
Not active: if you are driving at speeds below
80 km/h following activation.
Extended range foglamps The extended range foglamps reduce the
glare experienced by the driver and improve
the illumination of the edge of the carriage-
way.
Active:
if you are driving at speeds below
70 km/h and you switch on the rear foglamp.
Not active: if you are driving at speeds above
100 km/h or if you switch off the rear foglamp following activation. Adaptive Highbeam Assist
G
WARNING
Adaptive Highbeam Assist does not recognise road users:
R who have no lights, e.g. pedestrians
R who have poor lighting, e.g. cyclists
R whose lighting is blocked, e.g. by a barrier
In very rare cases, Adaptive Highbeam Assist
recognises road users too late or not at all. In
this, or in similar situations, the automatic Exterior lighting
109Lights and windscreen wipers
Z

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 are under 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 con-
tacts of the xenon bulb. Always have work on the xenon bulbs carried out at a qualified spe- cialist workshop.
If your vehicle is equipped with xenon bulbs,
you can recognise 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 plug connectors can
become very hot during use. When replacing a bulb, you could burn yourself on these com-
ponents. There is a risk of injury.
Allow these components to cool down before replacing the bulb.
There are bulbs other than the xenon bulbs
that you cannot replace. Replace only the bulbs listed (Y
page 112). Have the bulbs that
you cannot replace yourself replaced at a
qualified specialist workshop.
If you require assistance replacing bulbs, con-
sult 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 fitting.
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 of bulb replacement – bulbs
You can replace the following bulbs. The
details for the bulb type can be found in the
legend. Halogen headlamps
:
Turn signal lamp: PY 21 W
; Main-beam headlamp/side lamp/park-
ing lamp: H15 55 W/15 W
= Dipped-beam headlamp: H7 55 W 112
Replacing bulbsLights and
windscreen wipers

Vehicles with Intelligent Light System
:
Cornering lamp: H7 55 W Tail lamp (halogen headlamps)
:
Reversing lamp: W 16 W
; Turn signal lamp: PY 21 W
= Tail lamp/brake lamp: W 16 W
? Rear foglamp: W 16 W
A Tail lamp: W 16 W Replacing the front bulbs
Fitting/removing the cover on the front wheel arch You must remove the cover from the front
wheel housing before you can change the
front bulbs. X
To remove: switch off the lights.
X Turn the front wheels inwards.
X Turn rotary knob :through 90°.
Cover ;is released.
X Push cover ;down.
X To fit: push cover ;up.
X Turn rotary knob :through 90°.
Cover ;is locked.
Dipped-beam headlamps (halogen
headlamps) G
WARNING
These bulbs are pressurised.
They can explode when being changed if:
R they are still hot
R they hit an object when being removed
R they are dropped
There is a risk of injury.
You should wear eye protection and clean
gloves when you are changing a bulb. If nec-
essary, have bulbs changed at a qualified spe- cialist workshop. Replacing bulbs
113Lights and windscreen wipers Z

X
Remove the cover in the front wheel arch
(Y page 113).
X Turn housing cover :anti-clockwise and
pull it out.
X Turn bulb holder ;anti-clockwise and pull
it out.
X Take the bulb out of bulb holder ;.
X Insert the new bulb into bulb holder ;.
X Insert bulb holder ;into the lamp and turn
it clockwise.
X Align housing cover :and turn it clock-
wise until it engages.
X Replace the cover in the front wheel arch
(Y page 113).
Main-beam headlamps and side lamps/ parking lamps (vehicles with halogen
headlamps) G
WARNING
These bulbs are pressurised.
They can explode when being changed if:
R they are still hot
R they hit an object when being removed
R they are dropped
There is a risk of injury.
You should wear eye protection and clean
gloves when you are changing a bulb. If nec-
essary, have bulbs changed at a qualified spe- cialist workshop. X
Switch off the lights.
X Open the bonnet. X
Turn housing cover :anti-clockwise and
pull it out.
X Turn bulb ;anti-clockwise and pull it out.
X Insert the new bulb and engage it to the
stop.
X Align housing cover :and turn it clock-
wise until it engages.
Turn signal lamp (halogen headlamps) X
Switch off the lights.
X Open the bonnet.
X Turn bulb holder :anti-clockwise and pull
it out.
X Take the bulb out of bulb holder :.
X Insert the new bulb into bulb holder :.
X Insert bulb holder :and turn it clockwise
until it engages.
Cornering lamps (Intelligent Light Sys-
tem) G
WARNING
These bulbs are pressurised.
They can explode when being changed if:
R they are still hot
R they hit an object when being removed
R they are dropped
There is a risk of injury.
You should wear eye protection and clean
gloves when you are changing a bulb. If nec-
essary, have bulbs changed at a qualified spe- cialist workshop. 114
Replacing bulbsLights and windscreen wipers

Combination switch
1
$ Windscreen wipers 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/ îto wipe the wind-
screen using washer fluid
X Turn the key to position 1or 2in the ignition
lock.
X Turn the combination switch to the corre-
sponding position.
! Vehicles with a rain sensor: if the wind-
screen becomes dirty in dry weather con-
ditions, the windscreen wipers may be acti-
vated inadvertently. This could damage the windscreen wiper blades or scratch the
windscreen.
For this reason, you should always switch
off the windscreen wipers in dry weather.
Vehicles with a rain sensor: in theÄor
Å position, the appropriate wiping fre-
quency is automatically set according to the
intensity of the rain. In the Åposition, the
rain sensor is more sensitive than in the Ä
position, causing the windscreen wipers to
wipe more frequently.
If the wiper blades are worn, the windscreen
will no longer be wiped properly. This could
prevent you from observing the traffic condi-
tions. Replace the wiper blades twice a year,
ideally in spring and autumn. Switching the rear window wiper on/
off Combination switch
:
è Switch
2 ô To wipe with washer fluid
3 ITo switch on intermittent wiping
4 0To switch off intermittent wiping
5 ô To wipe with washer fluid
X Turn the key to position 1or 2in 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 windscreen wipers begin to move while
you are changing the wiper blades, you can be trapped by the wiper arm. There is a risk of
injury.
Always switch off the windscreen wipers and
ignition before changing the wiper blades.
! To avoid damaging the windscreen wiper
blades, make sure that you touch only the
wiper arm of the windscreen wiper.
! Never open the bonnet/tailgate if a wiper
arm is folded away from the windscreen/
rear window. Windscreen wipers
117Lights and windscreen wipers Z

Problems with the rear window heating
Problem
Possible causes/consequences and
M
MSolutions The rear window heat-
ing has switched off
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 heat- ing can be activated again. Activating/deactivating air-recircula-
tion mode
If you switch on air-recirculation mode, the
windows can mist up more quickly, in partic-
ular at low temperatures. Only use air-recir-
culation mode briefly to prevent the windows misting up.
You can deactivate the flow of fresh air if
unpleasant odours are entering the vehicle
from outside. The air already inside the vehi-
cle will then be recirculated.
The operation of air-recirculation mode is thesame for all control panels.
X Turn the key to position 2in the ignition
lock (Y page 143).
X To activate: press theebutton.
The indicator lamp in the ebutton lights
up.
i Air-recirculation mode is activated auto-
matically 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 theebutton.
The indicator lamp in the ebutton goes
out. i
Air-recirculation mode deactivates auto-
matically:
R after approximately five minutes at out-
side temperatures below approximately
5 †.
R after approximately five minutes if the
"Cooling with air dehumidification" func-
tion is deactivated.
R after approximately 30 minutes at out-
side temperatures above approximately
5 †a nd when the "Cooling with air dehu-
midification function" is activated. Convenience opening/closing using
the air-recirculation button
G
WARNING
When the convenience closing feature is oper- ating, parts of the body could become trapped
in the closing area of the side window and the
sliding sunroof. There is a risk of injury.
Observe the complete closing procedure
when the convenience closing feature is oper-
ating. When closing make sure that no parts of the body are in the closing area. G
WARNING
During convenience opening parts of the body could be drawn in or become trapped
between the side window and window frame.
There is a risk of injury.
When opening, make sure that nobody is
touching the side window. If someone
becomes trapped, press the Wswitch 132
Operating the climate control systemClimate control

Problem
Possible causes/consequences and
M
MSolutions Vehicles with a petrol
engine:
The engine is not run-
ning smoothly and is
misfiring. There is a malfunction in the engine electronics or in a mechanical
component of the engine management system.
X Only depress the accelerator pedal slightly.
Otherwise, non-combusted fuel may get into the catalytic con-
verter and damage it.
X Have the cause rectified immediately at a qualified specialist
workshop. The coolant tempera-
ture display is showing
more than 120 †. The
coolant warning lamp
may also be on and a
warning tone may
sound. The coolant level is too low. The coolant is too hot and the engine
is no longer being cooled sufficiently.
X Stop as soon as possible and allow the engine and the coolant to
cool down.
X Check the coolant level (Y page 288). Observe the warning
notes as you do so and top up the coolant if necessary. If the coolant level is correct, the engine radiator fan may be faulty.
The coolant is too hot and the engine is no longer being cooled
sufficiently.
X If the coolant temperature is below 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving in
mountainous terrain and stop-start traffic. Manual transmission
Gear lever
! Only engage gear when the clutch pedal is
depressed.
! When shifting to
5thand 6thgear, you
must press the shift lever to the right. Oth- erwise, you could shift unintentionally into
3rd or4th gear and damage the engine or
transmission.
If you shift down at too high a speed (trans-
mission braking), this can cause the engine
to overrev, leading to engine damage.
Do not use the clutch bite point to keep the vehicle stationary on uphill gradients.
There is otherwise a risk of damaging the
clutch.
! On long and steep downhill gradients,
especially if the vehicle is laden or towing a trailer, you must shift into gear
1, 2or3in
good time. This uses the engine's braking
effect. This relieves the load on the brake
system and prevents the brakes from over-
heating and wearing too quickly. Gear lever
k
Reverse gear
1 to6
Forward gears 150
Manual transmissionDriving and parking

cle from rolling away by applying the parking
brake.
Vehicles with manual transmission X
Shift to either first gear or reverse gear R.
X Turn the key to position 0in the ignition
lock and remove it.
The immobiliser is activated.
X Apply the electric parking brake.
Vehicles with automatic transmission All vehicles (except AMG vehicles)
X Apply the electric parking brake.
X Shift the transmission to position P.Selector lever in AMG vehicles
AMG vehicles:
X Apply the electric parking brake.
X Press Pbutton :.
X Turn the key to position 0in the ignition
lock and remove it.
The immobiliser is activated.
i If you switch the engine off with the trans-
mission in position Ror D, the automatic
transmission shifts to Nautomatically.
If you then open one of the front doors or
remove the key from the ignition, the auto-
matic transmission shifts to P.
If you shift the automatic transmission to N
before switching off the engine, the auto-
matic transmission remains in Neven if a
door is opened. Electric parking brake
General notes G
WARNING
If you leave children unattended in the vehi-
cle, they could set the vehicle in motion by, for example:
R releasing the parking brake
R shifting an automatic transmission out of
parking position P
R shifting a manual transmission into neutral
R starting the engine
They could also operate vehicle equipment.
There is a risk of an accident and injury.
When leaving the vehicle, always take the key with you and lock the vehicle. Never leave
children unattended in the vehicle. i
The electric parking brake carries out a
function check at regular intervals when
the engine is switched off. Noises that
occur are normal.
Engaging/releasing manually Engaging
X Push handle :.
When the electric parking brake is applied,
the ! red indicator lamp lights up in the
instrument cluster.
i The electric parking brake can also be
applied when the key is removed. Parking
163Driving and parking Z