Key MERCEDES-BENZ M-Class 2012 W166 Service Manual

Aut
oma tic hea dlamp mod e X
To swit chon autom atic hea dlamp
mod e:tur nth eligh tswit chtoc or
Ã.
Sm artKey inpos ition 1in theign ition lock:
th epark inglamp sare swit ched on oroff
auto maticallydepe nding onthebrig htne ss
of theambi entlight .
With theenginerunn ing:depen dingonthe
bright nessof the ambien tlight ,the daytime
runn inglamps 6
or the low-be amheadlamps
are switc hedonoroff autom atically.
When thelow-be amheadlamps are
switc hedon,the L indicatorlamp inthe
inst rumen tcluster lightsup. G
WARN
ING If
the light switc his set toc orÃ, the
low-be amheadlamps willnotcom eon
autom atically ifit is fogg y.This could
endan geryou and others. There fore,tur nthe
light switch toL infog.
The automatic headlampfeature isonly an
aid. Thedriver isresponsible forthe vehicle's
lighting atall times.
Rear foglamp X
To switch onthe rear foglamp: turnthe
SmartK eyinthe ignition locktoposition 2
or start theengine.
X Turn thelight switch toL orc or
Ã.
If the light switch isset toc orÃ,
the rear foglamp onlylights upifthe low-
beam headla mpsareon.
X Press theR button.
The yellow R indicator lampinthe
instrumen tcluster lightsup.
X To switch offther ear foglam p:pres sth e
R button.
The yellow Rindicatorlamp inthe
ins trumen tcluster goesout. i
If
you switc hthe engineoff(Sm artKey in
posit ion1in the ignit ionlock )and then
rest artit,the prev ious rearfoglamp
set tings are rest ored.
Rea rfog lamp X
To switch ontherea rfog lamp:tur nthe
Sm artKey inthe ignit ionlock toposit ion2
or start the engin e.
X Turn thelight switc hto L orc or
Ã.
If the light switc his set toc orÃ,
the rear foglamp onlylightsup ifthe low-
beam headlamps areon.
X Press theR button.
The yellow Rindicatorlamp inthe
inst rumen tcluster lightsup.
X To switch offther ear foglam p:pres sth e
R button.
The yellow Rindicatorlamp inthe
ins trumen tcluster goesout. i
If
you switc hthe engineoff(Sm artKey in
posit ion1in the ignit ionlock )and then
rest artit,the prev ious rearfoglamp
set tings are rest ored.
Head lampcleaning system The
headlamps areclean edautomat icallyif
the "Wipe withwasher fluid"function is
operat edten timeswhile thelight sare onand
the engin eis runn ing(Ypage 118).When you
switc hoff the ignit ion,theautomat ic
headlamp cleaningsyste misreset and
counting isresumed from0.
6 Only ifdaytime runninglampshavebeen activated viathe on-board computer. 110
Exterior
lightingLights and windshield wipers

Comb
inationswit ch
Tu rn signa ls :
High-beam headlam ps
; Right turns ignal
= High- beam flasher
? Left turnsign al
X To indica tebrief ly:press thecom binat ion
switc hbrief lyto the press urepoint inthe
direc tionofarrow ;or?.
The correspo ndingtur nsignal flashes three
tim es.
X To indica te:press thecom binat ionswitc h
beyond thepress urepoint inthe direc tion
of arrow ;or?.
High- beam headlamps X
To switch ontheh igh-b eamhead lamps:
turn theSmar tKey inthe ignit ionlock to
posit ion2or star tthe engin e.
X Turn thelight switc hto L orc or
Ã.
X Press thecom binat ionswitc hbeyond the
pressure pointinthe direct ionof
arrow :.
In the c orà position ,the high-
beam headlamps areonly switched on
when itis dark andtheengin eis runn ing. The
K indicat orlamp inthe instrument
cluster lightsupwhen thehigh-beam
headlamps areswitch edon.
X To switch offthe high-bea m
headla mps:move thecombin ationswitch
back toits norm alposition .
The K indicat orlamp inthe instrument
cluster goesout.
High-beam flasher X
To switch on:turn theSmart Keyinthe
ignition locktoposition 1or 2or start the
engin e.
X Pull thecombin ationswitch inthe direct ion
of arrow =. Haz
ard warning lamps The
hazard warning lampsautomatic ally
switch onif:
R an air bag isdeployed.
R the vehicle isslowed downseverely froma
speed ofover 45mph (70km/ h)and comes
to ahalt.
X To switch onthe hazard warning lamps:
press button :.
All turn signals flash.Ifyou now switch on
a turn signal usingthecombin ationswitch ,
only theturn signal lamponthe
corr espondin gside ofthe vehicle willflash.
X To switch offthe hazard warning
lamp s:press button :. Exterior
lighting
111Lights and windshield wipers Z

The
system cannotrecogn izethe following
road users:
R Road users without alighting systemof
their own, e.g.pedestrians
R Road users withdimlighting oftheir own,
e.g. cyclists
R Road users whose lighting isobstruct ed,
e.g. road users behind aguardrail
R Insome seldom cases,evenroadusers with
a lighting systemoftheir ownmay be
recogn izedtoolate ornot atall.
The automatic high-beam headlamps willthen
not bedeactivated oritwill beactivated in
spite ofpreceding oroncom ingroad users.
This could endanger youand/or othersand
cause anaccident .Always payclos eatt ent ion
to the traffic situat ionand switc hoff the high
beam manually ifnec essary. Head
lampsfogged upontheinside
The headlamps mayfogupon the inside if
the reishigh atmo spher ichumidit y.
X Dr ive with theheadlamps switchedon.
The level ofmoist uredimin ishes,
depen dingonthe lengt hof the jour ney and
the weather condition s(humidit yand
tem perat ure).
If the level ofmoist uredoes notdimin ish:
X Have theheadlamps checkedataqualified
spec ialist workshop. Inter
iorlight ing Over
view ofinter iorlight ing Over
head control panel
: p Toswitc hthe left-han dfro ntreadin g
lamp on/off
; c Toswitc hthe frontinterior lighting
on
= v Toswitc hthe rear interior lighting
on/ off
? | Toswitc hthe frontint erior lighting/
autom aticinterior lightingcon trol off
A p Toswitc hthe right -handfront
read inglamp on/off
B Toswi tch the automatic interiorlighting
control on Inte
rior lighting control
Important notes In
order toprevent thevehicl e'sbattery from
discha rging,theinterior lighting functions are
au tomatical lydea ctivated aftersome time
except forwhen theSmartKey isin posi tion
2 in the ignitio nlock.
The color andbrigh tness ofthe ambi ent
lig hting maybeset using the on-board
computer (Ypag e234).
Automatic interiorlight ingcontr ol X
To switch on:setthe rocker switc hto
cen terposit ionB. Inter
iorlight ing
113Lights and windshield wipers Z

X
To switcho ff:set the rocker switch tothe
| position.
The interior lighting automatical lyswitches
on ifyou :
R unlock thevehicl e
R open adoor
R remove theSmartKey fromtheignitio nlock
The interior lightisactivated forashort while
when theSmart Keyisremoved fromthe
ignition lock.Youcanactivate thisdelay ed
switch- offusing theon-board computer
(Y page 235).
Manua linterior lighting control X
To switch thefront interior lighting on:
set the rock erswitch tothe c position.
X To switch thefront interior lighting off:
set the rock erswitch tothe | position.
X To switch therear interior lighting on/
off: press theu button .
X To switch thereading lampson/off:
press thep button . Crash-
responsive emergency lighting
The interior lighting isactivated automatically
if the vehicle isinvolved inan accident .
X To switch offthe crash- responsive
emergency lighting:pressthehazard
warning lampbutton .
or
X Lock andthen unlock thevehicle usingthe
Smart Key. Replacing
bulbs Import
antsafety notes
Xenon bulbs If
your vehicle isequipped withXenon bulbs,
you can recogn izethis bythe following: the
cone oflight from theXenon bulbsmoves
from thetop tothe bottom andback again when
youstart theengine. Forthis tobe
observed, thelights mustbeswitched on
before startingthe engine. G
DANGER Xenon
bulbscarryahigh voltage. Youcould
get anelectric shockandbeseriously oreven
fatally injured ifyou touch theelectric
cont acts onXenon bulbs.Therefore, never
remove thecover fromXenon bulbs.
Do not change Xenonbulbsyourself, buthave
them replaced ataquali fiedspecialist
workshop whichhasthenecessary specialist
knowledge andtools tocarry outthework
required.
Mercedes-B enzrecommen dsthat youusean
authorized Mercedes-B enzCenter forthis
purpose. Inparticular, workrelevant tosafety
or on safety-related systemsmustbecarried
out ataquali fiedspecialist workshop.
Bulbs andlamps areanimportant aspectof
vehicle safety.Youmust therefor emake sure
that these functioncorrec tlyatall times.
Have theheadlamp settingcheck edregularly .
Other bulbs There
arebulbs otherthantheXenon bulbs
that youcann otreplace. Replaceonly the
bulbs listed (Ypage 115). Havethebulbs that
you cann otreplace yourself changed ata
quali fiedspecialist workshop.
Mercedes-B enzrecomm endsthatyouusean
authorized Mercedes-B enzCenter forthis
purpose. Inparticular, workrelevant tosafety
or on safety-related systemsmustbecarried
out ataquali fiedspecialist workshop.
If you require assistance changingbulbs,
consult aquali fiedspecialist workshop.
Do not touch theglass tubeofnew bulbs with
your bare hands. Evenminor contamination
can burn intotheglass surface andreduce
the service lifeofthe bulbs. Always usealint-
free cloth oronly touch thebase ofthe bulb
when installing.
Only usebulbs ofthe correc ttype. 114
Rep
lacingbul bsLights an dwindshield wipers

4
e Toswitch offinter mittentwiping
5 b Towipe withwasher fluid
X Turn theSmart Keytoposition 1or 2in the
ignition lock.
X Slide switch :onthe combinat ionswitch
up ordown tothe appropriate position.
When therear window wiperisswitched on,
the icon appears inthe instr ument cluster. Replacing
thewiper blades
Impor tantsafety notes G
WARNIN
G For
safety reasons, switchoffthe windshield
wipers andremove thekey from theignition
lock before changin gthe wiper blades
(vehicles withKEYLE SS-GO: make surethat
the on-board electronicsare instate 0).
Otherwise, thewiper motor couldbeswitched
on suddenly andcause injury.
! Toavoid damaging thewiper blades,
make surethatyoutouch onlythewiper
arm ofthe wiper.
! Never openthehood ifawindshield wiper
arm hasbeen folded awayfromthe
windshield.
Never foldawindshield wiperarmwithout
a wiper bladebackontothe windshield/
rear window.
Hold thewindshield wiperarmfirmly when
you change thewiper blade. Ifyou release
the windshield wiperarmwithout awiper
blade anditfalls ontothe windshield, the
windshield maybedamaged bythe force of
the impact.
Mercedes- Benzrecomm endsthatyouhave
the wiper blades replaced byaq ualifi ed
spec ialist workshop,e.g. at an auth orized
Mer cedes- BenzCent er. Changing
thewindshield wiperblades Removing
thewiper blades
X Remove theSmart Keyfrom theignition
lock.
X Fold thewiper armaway fromthe
windshield. X
Firmly pressrelease knob : and pullthe
wiper bladeupwards fromthewiper armin
the direct ionofthe arrow.
Installing thewiper blades
X Position thenew wiper bladeinthe retain er
on the wiper armandslide itint oplace in
the opposite directiontothe arrow.
The wiper bladeaudibly engages.
X Make surethatwiper bladeisseated
corr ectly.
X Fold thewiper armback ontothe
windshield.
Repla cingtherear window wiperblade Removing
thewiper blade G
WARN
ING The
wiper armcould beset inmotion and
injur eyou ifthe wiper isswitch edon.
Remove thekey from theignition lockbefore
replacing thewiper blade. Windsh
ieldwipers
119Lights and windshield wipers Z

X
Remo vetheSm artKey from theign ition
loc k.
X Fo ldwiper arm:away from therear
win dow untilit en gage s.
X Pos ition wiper blade;atarig ht ang leto
wiper arm:.
X Ho ldwiper arm:and presswiper
blade ;inthedir ection ofthearr ow until
it rel ease s.
X Remo vewiper blade;.
Inst alling thewipe rblad e
X Place newwiper blade;ontowiper
arm :.
X Hold wiper arm:and press wiper
blade ;inthe opposit edirec tiontothe
arrow untilit engage s.
X Make surethatwiper blade;isseated
cor rectly.
X Posit ionwiper blade;parallel towiper
arm :.
X Fold wiper arm:back ontothe rear
window. Problem
swith thewindshield wipers
Th ewindshield wipersareobstr ucted Leaves
orsno w,for examp le,may be
obst ructingthe windsh ieldwiper movement.
The wiper motorhas been deact ivated . X
For safet yreason s,you should removethe
Smar tKey from theignit ionlock .
or
X Swit choff the engin eusing theStart/ Stop
butt onand open thedriver 'sdoor.
X Remove thecause ofthe obst ruction.
X Swit chthe windsh ieldwipers backon.
Th ewindshield wipersareinoper ative The
windsh ieldwiper driveismalfun ctionin g.
X Selec tanothe rwiper speed onthe
com binat ionswitc h.
X Have thewinds hieldwipers checkedata
qualified specialist workshop.
Th espr aynozz lesaremisa ligned The
winds hieldwasher fluidfromt hespray
nozz lesnolonger hitsthecent erofthe
windshield. Thespray nozzlesare misaligned.
X Have thespray nozzlesadjusted ata
qual ified specialist workshop. 120
Windshield
wipersLights and windshield wipers

norm
aland notasign tha tther eis a
ma lfunctio n. i
The
cooling with aird ehumidification
func tion uses refriger antR134a. This
coolant doesnotcontain
chlorof luorocarbon s,and therefore does
not damage theozon elayer.
Activating/d eactivating X
To activa te:press the¿/Á button.
The indicat orlamp inthe ¿/Á
button lightsup.
X To deactiva te:press the¿/Á
button .
The indicat orlamp inthe ¿/Á
button goesout.Thecooling withair
dehumidification function hasadelayed
switch -offfeature.
Problems withthecooling withair
dehum idificat ionfunction When
youpress the¿/Á button,the
indicat orlamp inthe button flashes three
times orremains off.You cannolonger switch
on the cooling withairdehumidification
func tion.
X Consult aqualified specialist workshop. Sett
ingclimat econtrol toaut omat ic G
WARN
ING If
you switch offthe cooling function,the
vehicle willnotbecooled whenweather
con ditions arewarm. Thewindows canfogup
more quickly. Window foggingmayimpair
visibility andendanger youand other s.
In automatic mode,thesettemper atureis
maint ained automatic allyatacon stan tlevel.
The system automatic allyregulates the
temper atureofthe dispensed air,the airflow
and theairdistribut ion.
Autom aticmode willachieve optimal
operation ifcooling withairdehumidification is
also activat ed.Ifdesired, coolingwithair
dehumidification canbedeactivat ed.
In the rear compart ment,you can also switch
climate control forthe rear seats toautomatic
mode usingtheà button .
X Turn theSmart Keytoposition 2in the
ignition lock.
X Set thedesired temperature.
X To activa te:press theà button .
The indicat orlamp inthe à button lights
up. Autom aticairdistribut ionand airflow
are activ ated. i
Autom
aticclimate control: when
automatic modeisactivat ed,you can
select aclimate modesetting
(Y page 129).
X To switch off:press the_ button .
or
X Press theI orK button .
The indicat orlamp inthe à button goes
out. Adju
sting theclimat emode settings
(AIR FLOW)
This function isonly available withautomatic
climate control.
The climate control settings areespecially
effec tiveathigh temper atures.
You canselect thefollowing climatecontrol
sett ings inautomatic mode:
FOCUS highairflow thatisset slightly
cooler
MED IUM medium airflow,standard setting
DIF FUS Elow airflow thatisset slightly
warmer andwith alower rateof
airflow Opera
tingtheclimate controlsystem
129Climate control Z

X
Turn theSmart Keytoposition 2in the
ignition lock.
X Press theà button .
X Press theñ button repeatedly untilthe
desired climatemodeappears inthe
display . Setting
thetemp erature
Climate control Differ
enttemperat urescanbeset forthe
driver's andfront-passenger sides.
X Turn theSmart Keytoposition 2in the
ignition lock.
X To increase/reduce: turncontrols:and
B clock wiseorcount erclock wise
(Y page 123).
Only change thetemperat uresettingin
small increm ents.Start at72 ‡(22 †).
3-zone automat icclimate control Automat
icclimate controlzones
You canselect different temperat uresett ings
for the driver's andfront-passenger sidesas
well asfor the rear compart ment.
X Turn theSmart Keytoposition 2in the
ignition lock.
X To increase/reduce thetemp eraturein
the front :turn controls:and B clock
wiseorcount erclock wise
(Y page 126).
Only change thetemperat uresettingin
small increm ents.Start at72 ‡(22 †).
X To increase/reduce thetemp eraturein
the rear compar tment using thefront
control panel:presstheá button .
The indicator lampinthe á button goes
out.
X Turn control: clock wiseor
count erclock wise(Ypage 126).
Only change thetemperat uresettingin
small increm ents.Start at72 ‡(22 †).
The temperat uresettingforthe driver's
side isadopted forthe rear compart ment
and thefron t-passenger side.
X To increase/decrease therear
compar tment temp eratureusing the
rear control panel:turncontrolM onthe
rear controlpanel clockwiseor
count erclock wise(Ypage 126).
Only change thetemperat uresettingin
small increm ents.Start at72 ‡(22 †). Setting
theairdistr ibution
Front control unit:
P Directsair through thecent ervent s.
O Directsthe airflow through the
footwell airvent s
S Directsthe airflow through thecent er
and footwell vents.
¯ Directsthe airflow through the
defrost ervent s
b Directsthe airflow through the
defrost erand cent ervent s10
a Directsthe airflow through the
footwell anddefrost ervent s
_ Directsthe airflow through the
defrost er,cent erand footwell air
vent s10
10 For Canada only. 130
Opera
tingtheclimate controlsystemClimate control

Rear
control panel:
M Directsthe airflo wthrou ghthe rear
center andrearsid eairvents.
O Directsthe airflo wthrou ghthe
footw ellai rv ent s i
Using
therear control panel, youcan also
activat eboth airdistribut ionposition s
simultaneously. Inorder todo this, press
both airdistribut ionbutton s.The airisthen
routed through allrear airvent s. i
Regardless
ofthe airdistribut ionsett ing,
airflow isalway sdirect edthrough theside
air vent s.The side airvent scan only be
closed whenthecontrols onthe side air
vent sare turn eddownwards.
X Turn theSmart Keytoposition 2in the
ignition lock.
X Front control panel:pressthe_
button repeatedly untilthedesired symbol
appears inthe display.
X Rear control panel:presstheM and/
or O button . Sett
ingthe airflow
X Turn theSmart Keytoposition 2in the
ignition lock.
X To increase: presstheK button .
X To redu ce:press theI button . i
You
canuseautomatic climatecontrol to
set the airflow inthe rear compart ment
separately. Switching
theZONE function on/off
X To switch on:press theá button .
The indicat orlamp inthe á button lights
up.
Dual-z oneautomatic climatecontrol: the
temper aturesettingforthe driver's sideis not
adopted forthe fron t-passenger side.
The temper atureofthe fron t-passenger
side isadopted forthe rear compart ment.
Autom aticclimate control: the
temper aturesettingforthe driver's sideis
not adopted forthe fron t-passenger side
and therear compart ment.
When thebutton sor con trols for
temper ature,airflow orair distribut ionare
activat ed,the temper aturesettingforthe
driver's sideisnot adopted forthe other
climate control zones.
X To switch off:press theá button .
The indicat orlamp inthe á button goes
out.
The temper aturesettingforthe driver's
side isadopted forthe fron t-passenger side
and therear compart ment. Defrosting
thewindshield
You canusethis func tion todefrost the
windshield ortodefrost theinside ofthe
windshield andtheside windows. i
You
should onlyselect thedefrost ing
func tion until thewindshield isclear again.
X Turn theSmart Keytoposition 2in the
ignition lock.
X To activa te:press the¬ button .
The indicat orlamp inthe ¬ button lights
up.
The climate control system switchestothe
following functions:
R cooling withairdehumidification on11
R high airflow 12
R high temper ature12
R air distribut iontothe windshield and
fron tside windows
R air-r ecirculat ionmode off
11 Only withenginerunn ing.
12 Depe ndingon the outs idetem perat ure. Oper
ating theclima tecontr olsyst em
131Climate control Z

X
To switchof f:pre ssthe ¬ button.
The indicator lamp inthe ¬ button goes
ou t.The previouslysel ecte dsettings come
int oeffec tagain. Thecooling withair
dehumidification functionremains on.Air-
recirculation moderemains deactivated.
or
X Press theà button .
The indicator lampinthe ¬ button goes
out. Airflow andairdistribution aresetto
automatic mode.
or
X Turn controls:orB clock wiseor
count er-clockwise (Ypage 123),
(Y page 123).
or
X Press theK orI button . Switching
maximumcool ingMAX
COOL on/off
The MAX COOL functionisonly availa blein
vehicles forthe USA .
MAX COOL isonly operational whenthe
engine isrunnin g.
When youactivate MAXCOOL, climate
cont rolswitches tothe following functions:
R maximum cooling
R maximum airflow
R air-recirc ulationmodeon
X To activat e:press theÙ button .
The indicator lampinthe button lightsup.
X To deactivat e:press theÙ button
again.
The indicator lampgoesout.Thepreviously
selected settings come intoeffect again. Defrosting
thewindows
Windows foggeduponthe inside X
Act ivate the¿/Á coolingwithair
dehumidification function.
X Act ivate automatic modeÃ.
X Ifthe windows continue tofog up,activate
the defrostin gfunct ion(Ypage 131). i
You
should onlyselect thissettinguntil
the windshield isclear again.
Windows foggeduponthe outside X
Act ivate thewindshield wipers.
X Press the_ button repeatedly untilthe
P orO symbol appears inthe
display . i
You
should onlyselect thissettinguntil
the windshield isclear again. Rear
window defroster
Activating/deactivat ing G
WARNING Any
accumulation ofsnow andiceshould be
removed fromtherear window beforedriving.
Visibility couldotherwise beimpaired,
endangering youand others.
The rear window defroster hasahigh current
draw. Youshould therefor eswitch itoff as
soon asthe window isclear asitonly switches
off automatically afterseveral minutes.
If the battery voltage istoo low, therear
window defroster mayswitch off.
X Turn theSmart Keytoposition 2in the
ignition lock.
X Press the¤ button .
The indicator lampinthe ¤ button lights
up orgoes out. 132
Opera
tingtheclimate controlsystemClimate control