2012 MERCEDES-BENZ GL SUV trailer

reasons concerning th
eoperating permit.
This also applie sincountries in which the
permissible maximum speed for vehicle/
trailer combinations is above 100 km/h.
When towing atrailer, your vehicle's handling
characteristics wil lbedifferen tincomparison
to when drivin gwithout atrailer and it will
consume more fuel.
On long and stee pdownhil lgradients ,you
must select shift range 1,2or 3in good time.
i This also applies if you have activated
cruise con trol, SPEEDTRONIC or DI S-
TRONIC PLUS.
This will use the brakin geffect of th eengine,
so les sbraking wil lberequired to prevent the
vehicle from gainin gspeed. This relieves the
load on the brak esystem and prevent sthe
brakes from overheating and wearing too
quickly .Ifyou need additional braking,
depress the brake pedal repeatedly rather
than con tinuously.
Driving tips If the trailer swings from sid
etoside:
X Do not accelerate.
X Do not countersteer.
X Brake if necessary.
R Maintain agreater distance from th evehi-
cle in front than when driving without a
trailer.
R Avoid braking abruptly. If possible, brake
gently at first to allow the trailer to run on.
Then, increase the braking force rapidly.
R The values given for gradient-climbing
capabilities from astandstill refer to sea
level. Whe ndriving in mountainou sareas,
note that th epower outpu tofthe engine,
and consequen tlyt he vehicle' sgradient-
climbing capability ,decrease with increas-
ing altitude. Folding out the ball coupling
G
WARNING
If the ball coupling is not correctly engaged,
the trailer can detach. There is arisk of an
accident.
Always engage the ball coupling as described. G
WARNING
If you release the ball coupling or it does not
engage correctly when folding in, it will swing
out. Within pivoting range of the ball coupling,
there is an increased risk of an accident and
injury.
Only release the ball coupling if the pivoting
range is unobstruc ted. Alway smake sure that
the ball coupling engages when folding in.
! AMG vehicles and vehicles with AMG
bodystyling: remove the cover below the
bumper before you fold out the ball cou-
pling. Otherwise, the ball coupling, the
cover and the bumper could be damaged.
Before you can tow atrailer with your vehicle,
yo um ust fold out the ball coupling.
X Make sure that the vehicle is stationary. X
AMG vehicles and vehicles with AMG
bodystyling: pull down cover :by han-
dle ;in the direction of the arrow until it
is released. Towin
gatrailer
259Driving an dparking Z

X
AMG vehicles and vehicles with AMG
bodystyling: release cover =from the
bracket at the rea rand sto witsafely. X
Open the tailgate.
X Pull release knob :until the ball coupling
unlocks.
The ball coupling folds out from under the
rear bumper.
The indicator lamp on the release knob
flashes .The trailer socket folds away auto-
matically. X
Press the ball couplin ginthe direction of
the arrow until it engages in avertical posi-
tion.
The indicator lam ponthe release knob
goes off.
The multifunction display shows the
Chec ktrailer hitch lock message
until th eball coupling is engaged.
X Remove the protective covering from the
ball coupling and store it in asafe place. Coupling up
atrailer
Important safety notes G
WARNING
Vehicles with level control:
If you disconnec tthe trailer cable, the vehicle
is lowered. This can cause you or other sto
become trapped between the vehicl ebody
and tyres, or underneat hthe vehicle. This
poses arisk of injury.
Make sure that no-on eisinthe immediate
vicinit yofthe wheel arch or underneath the
vehicle when disconnectin gthe trailer cable.
Vehicles with th eAIRMATIC package X
Make sure that the transmission is in posi-
tion P.
X Engage the electric parking brake.
X Start the engine.
X Set the vehicle to highway level
(Y page 213).
X Set the Adaptive Damping System (ADS )to
AUTO orCOMF (Ypage 212).
X Switch off the engine.
X Close the doors and tailgate.
X Position the trailer level behind the vehicle.
X Coupl eupthe trailer.
X Establish the electric con nectio nbetween
the vehicle and the trailer.
X Check that the trailer lighting system is
working. 260
Towing
atrailerDriving an dparking

i
If yo uhave coupled atrail er,the vehicle
will remain at highwa ylevel.
The vehicle automatically lowers to high-
way level if you driv efaster than 30km/h
with atrailer. The vehicle is not lowered to
high-speed level even if you are travelling
at higher speeds.
This also applies when using accessories
that are plugged int othe socket of the
trailer tow hitc h(e.g .ab icycle rack). Uncoupling
atrailer
Importan tsafety notes G
WARNING
If yo uuncoupl eatrailer with an engaged over-
ru nb rake ,you coul dtrap your hand be tween
th ev ehicle and th etrailer drawbar .This poses
ar isk of injury.
Do not uncouple atrailer wit hanengaged
overrun brake. G
WARNING
Vehicle swith level control:
If you disconnec tthe trailer cable, the vehicle
is lowered. This can cause you or other sto
become trapped between the vehicl ebody
and tyres, or underneat hthe vehicle. This
poses arisk of injury.
Make sure that no-on eisinthe immediate
vicinit yofthe wheel arch or underneath the
vehicle when disconnectin gthe trailer cable.
! Do not disconnec tatrailer with an
engaged overrun brake. Otherwise, your
vehicl ecould be damaged by the rebound-
ing of the overru nbrake.
! Remove th einstalled adapter cable
before folding in the ball coupling. Other-
wise, damage may occur to the rear
bumpe rand the adapter cable. Vehicle
swith the AIRMATIC package X
Make sure that the transmission is in posi-
tion P.
X Engage the electric parking brake.
X Star tthe engine.
X Close the doors and tailgate.
X Secur ethe trailer against rolling away.
X Remove the trailer cable and decouple the
trailer.
X Switc hoff th eengine. Folding in the ball coupling
G
WARNING
If you releas ethe ball coupling or it does not
engage correc tlyw hen folding in, it will swing
out. Within pivotin grange of the ball coupling,
there is an increased risk of an accident and
injury.
Only release the ball coupling if the pivoting
range is unobstructed. Always make sure that
the ball coupling engages when folding in.
Fold the ball coupling back in if you are not
using the trailer tow hitch.
X Make sure that the vehicle is stationary and
the trailer cables are disconnected.
X Place the protective covering on the ball
coupling.
X Open the tailgate. Towin
gatrailer
261Driving an dparking Z

X
Pull release knob :until the ball coupling
unloc ks.
The ball coupling folds down from under the
rea rbumper. The indicator lamp on the
release knob flashes.
i Do not attempt to spee dupthis process
by usin gyour foot to apply additional pres-
sure .Otherwise, the syste mmay sustain
mechanical damage. X
Press the ball coupling in the direction of
the arrow until it engages audibl ybehind
the bumper.
The indicator lam ponthe release knob
goes out and the message in the multifunc-
tion displa ydisappears. X
AMG vehicles and vehicles with AMG
bodystyling: attachhooks ;of cover =
in the direction of the arrow int oopen-
ings :intended for this purpose. X
AMG vehicle sand vehicles with AMG
bodystyling: push cover?upwards in the
direction of the arrow until it engages.
X AMG vehicles and vehicles with AMG
bodystyling: check that cover ?has been
atta ched correctly. Trailer powe
rsupply
! Youc an connect accessories with a
power rating of up to 240 Wtothe perma-
nen tpower supply and with apower rating
of up to 18 0Wto the powe rsupply that is
switched on via the ignition lock.
The trailer batter ymay not be charged from
the power supply.
When it leaves the factory, your vehicle's
trailer socket is equippe dwithapermanent
power supply and apower supply that is
switched on via the ignition lock.
The permanen tpower supply is supplied via
trailer socket pin 9.
The power supply that is switched on via the
ignition lock is supplied via trailer socket pin
10.
The trailer's permanen tpower supply is
switched off in the even toflow vehicle supply
voltage and after six hour satthe latest.
You can fin dmore information about fit ting
the trailer electric sataqualified specialist
workshop.
X To switch the connected power supply
on or off: turn the key in the ignition lock 262
Towin
gatrailerDriving an dparking

to position
2or 0respective ly
( Y page 159). Bulb fa
ilure indicato rfor LEDl amps
i If LED lamps ar efitted in the trai ler, an
error message ma yappea rinthe multi-
function display eve nifthere is no fault .The
reason for the err or message could be that
the curren thas fallen below the minimum
of 50 mA.
To ensur ereliable operation of the bulb failure
indicator, each LE Dchain in the trailer lighting
must be guaranteed aminimum curren tof
50 mA. Trailer wit
h7-pin connector
General notes Trailers with 7-pi
nconnector: you can
make aconnection to the 13 -pin connector
on the ball coupling using an adapter plug or,
if necessary, an adapter cable. Bot hcan be
obtained in aqualified specialist workshop.
Fitting the adapter !
Make sure that there is sufficien tcable
play so that the cable cannot become
detached when cor nering.
! Remove th einstalled adapter cable
before folding in the ball coupling. Other-
wise, damage may occur to the rear
bumpe rand the adapter cable. X
Ope nthe socket cover.
X Inser tconnector with lug :into
groove ;of the socket. Tur nthe connec-
tor cloc kwise to the stop.
X Let the cover engage.
X If you are using an adapter cable, secure
the cable to the trailer with cable ties. Towing
atrailer
263Driving an dparking Z

Problems wit
htrailer towing Problem Possible causes/consequences and
M Solutions
The released ball cou-
pling cannot be
engaged. X
Visit aqualified specialist workshop. The ball coupling does
not unlock, even
though:
R
the vehicle is station-
ary
R no trailer cable is
connected
R the release knob to
unlock the ball cou-
pling has been pulled
for more than asec-
ond. The on-boar
dvoltage is insufficient.
X Start the engine.
If the ball coupling still does not unlock:
X Visit aqualified specialist workshop. 264
Towin
gatrailerDriving an dparking

Safety systems
Display messages Possible causes/consequences and
M Solutions
!÷
currentl
yunavail‐ able See Owner's
Manual ABS (Anti-loc
kBraking System) ,ESP ®
(Electronic Stability Pro-
gram), BAS (Brake Assist), PRE-SAFE ®
,t he HOL Dfunction, hill
start assist, crosswind driving assistance and ESP ®
trailer stabili-
sation are temporarily not available.
The adaptive brake lights ,COLLISION PREVENTION AS SIST, BAS
PLUS and PRE-SAFE ®
Brake may als ohave failed.
In addition, the ÷,åand! warning lamps light up in
the instrumen tcluster.
ATTENTION ASSIST is deactivated.
Possible causes:
R self-diagnosis is not yet complete.
R the on-board voltage may be insufficient.
G WARNING
The brake system continues to func tion normally, but withou tthe
func tions listed above. The wheels coul dtherefore lock if you
brake hard, for example.
The steerability and brakin gcharacteristics ma ybeseverely affec-
ted. The braking distance in an emergency braking situation can
increase.
If ESP ®
is not operational, ESP ®
is unabl etos tabilise the vehicle.
The dange rofskidding and having an accident increases.
X Carefull ydrive on asuitable stretch of road, making slight steer-
ing movement sataspeed above 20 km/h.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit aqualified specialist workshop. !÷
inoperativ
eSee Owner's Manual ABS, ESP
®
,B AS ,PRE-SAFE ®
,t he HOL Dfunction, hill start assist,
crosswind driving assistance and ESP ®
trailer stabilisation are not
available due to amalfunction.
The adaptive brake lights ,COLLISION PREVENTION AS SIST, BAS
PLUS and PRE-SAFE ®
Brake may als ohave failed.
In addition, the J,÷,åand! warning lamps light
up in the instrumen tcluster.
ATTENTION ASSIST is deactivated.
G WARNING Display messages
291On-board computer and displays Z

Displa
ymessages Possible causes/consequences and
M Solutions
The brak
esystem con tinues to function normally, but without the
function slisted above. The wheels could therefore loc kifyou
brake hard ,for example.
The steerabilit yand braking characteristics may be severely affec-
ted. The braking distance in an emergenc ybraking situatio ncan
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilis ethe vehicle.
The danger of skidding and having an accident increases.
X Drive on carefully.
X Visit aqualified specialist worksho pimmediately. ÷
currentl
yunavail‐ able See Owner's
Manual ESP
®
,B AS, PRE-SAFE ®
,t he HOL Dfunction, hill start assist, cross-
wind driving assistance and ESP ®
trailer stabilisatio nare not avail-
ab ledue to amalfunction.
The adaptive brake lights, COLLISION PREVENTION ASSIST, BAS
PLUS and PRE-SAFE ®
Brake may als ohave failed.
In addition, the ÷andå warning lamp slight up in the
instrument cluster.
The self-diagnosi sfunction may not be complete, for example.
ATTENTION ASSIS Tisd eactivated.
G WARNING
The brak esystem continues to function normally, but witho utthe
functions listed above. Th ewheels could therefor elock if you
brake hard ,for example.
The brakin gdistance in an emergenc ybraking situatio ncan thus
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilis ethe vehicle.
The danger of skidding and having an accident increases.
X Carefully drive on asuitable stretc hofroad, makin gslight steer-
ing movement sataspeed above 20 km/h.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit aqualified specialist workshop. 292
Display messagesOn-board computer and displays