2012 MERCEDES-BENZ GLK SUV trailer

G
WARNING
You could lose control of the vehicle/trailer
combination if it begins to swerve. The vehi-
cle/trailer combination could even overturn.
There is a risk of an accident.
On no account should you attempt to
straighten out the vehicle/trailer combina-
tion by increasing speed. Decrease your
speed and do not countersteer. Brake if nec-
essary. G
WARNING
If you exceed the permissible noseweight
while carrying a load, the carrier system could
detach from the vehicle and fall on the road.
There is a risk of an accident and injury.
Always maintain the permissible noseweight
when carrying loads.
! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
You can use carrier systems, e.g. bicycle
racks or load-bearing implements, on the ball
coupling. The maximum noseweight of
75 kg applies when using carrier systems on
the ball coupling.
When using a detachable trailer coupling,
make sure you observe the trailer coupling
manufacturer's operating instructions.
When reversing the vehicle towards the
trailer, make sure there is nobody between
the trailer and the vehicle.
Couple and uncouple the trailer carefully. If
you do not couple the trailer to the towing
vehicle correctly, the trailer could become
detached.
Make sure that the following values are not
exceeded:
R the permissible trailer drawbar noseweight
R the permissible trailer load R
the permissible rear axle load of the towing
vehicle
R the maximum permissible gross vehicle
weight of both the towing vehicle and the
trailer
The applicable permissible values, which
must not be exceeded, can be found:
R in the vehicle documents
R on the identification plates of the trailer tow
hitch, the trailer and the vehicle
If the values differ, the lowest value applies.
You will find the values approved by the man-
ufacturer on the vehicle identification plates
and those for the towing vehicle under "Tech-
nical data".
When towing a trailer, your vehicle's handling
characteristics will be different in comparison
to when driving without a trailer.
The vehicle/trailer combination:
R is heavier
R is restricted in its acceleration and gradi-
ent-climbing capability
R has an increased braking distance
R is affected more by strong crosswinds
R demands more sensitive steering
R has a larger turning circle
This can impair the vehicle's handling char-
acteristics. Adapt your style of driving accord-
ingly. Maintain a safe distance. Drive care-
fully.
When towing a trailer, always adjust your
speed to the current road and weather con-
ditions. Do not exceed the maximum permis-
sible speed for your vehicle/trailer combina-
tion.
General notes i
When towing a trailer, set the tyre pres-
sure on the rear axle of the towing vehicle
for a maximum load; see the tyre pressure
table in the fuel filler flap (Y page 353).
You will find fitting dimensions and loads in
the "Technical data" section (Y page 373).216
Towing a trailerDriving and parking

The maximum noseweight of the trailer draw-
bar on the ball coupling is 80 kg. However,
the actual noseweight may not be higher than
the value which is given on the trailer tow
hitch or trailer identification plates. The low-
est weight applies.
! Use a drawbar noseweight as close as
possible to the maximum permissible nose-
weight. Do not use a noseweight of less
than 50kg, otherwise the trailer may come
loose.
Note that the payload and the rear axle load
are reduced by the actual payload.
i The height of the ball coupling changes
with the load of the vehicle. If necessary,
use a trailer with a height-adjustable draw-
bar.
Driving tips i
Observe the notes on ESP ®
trailer stabi-
lisation (Y page 69).
The maximum permissible speed for vehicle/
trailer combinations depends on the type of
trailer. Before beginning the journey, check
the trailer's documents to see what the max-
imum permitted speed is. Observe the legally
prescribed maximum speed in the relevant
country.
For certain Mercedes-Benz vehicles, the max-
imum permissible rear axle load is increased
when towing a trailer. Refer to the "Technical
data" section to find out whether this applies
to your vehicle. If you utilise any of the added
maximum rear axle load when towing a trailer,
the vehicle/trailer combination may not
exceed a maximum speed of 100 km/h for
reasons concerning the operating permit.
This also applies in countries in which the
permissible maximum speed for vehicle/
trailer combinations is above 100 km/h.
When towing a trailer, your vehicle's handling
characteristics will be different in comparison
to when driving without a trailer, and it will
consume more fuel. Change into a lower gear in good time on long
and steep downhill gradients. On vehicles
with automatic transmission, you have to
select shift range
1,2or 3.
i This also applies if you have activated
cruise control or SPEEDTRONIC.
This will use the braking effect of the engine,
so less braking will be required to prevent the
vehicle from gaining speed. This relieves the
load on the brake system and prevents the
brakes from overheating and wearing too
quickly. If you need additional braking,
depress the brake pedal repeatedly rather
than continuously.
Driving tips R
Maintain a greater distance from the vehi-
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 a standstill refer to sea
level. When driving in mountainous areas,
note that the power output of the engine,
and consequently the vehicle's gradient-
climbing capability, decrease with increas-
ing altitude.
If the trailer swings from side to side:
X Do not accelerate.
X Do not countersteer.
X Brake if necessary. Fitting the ball coupling
X Make a note of the ball coupling key num-
ber.
i You can use this number to obtain a
replacement key from a Mercedes-Benz
Service Centre. Towing a trailer
217Driving and parking Z

G
WARNING
If the ball coupling is not correctly engaged, it
could detach while driving and fall on the road.
There is a risk of an accident and injury.
Engage the ball coupling as described. G
WARNING
If the ball coupling is not correctly engaged,
the trailer can detach. There is a risk 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 unobstructed. Always make sure that
the ball coupling engages when folding in.
The detachable ball coupling is located in the
stowage well under the luggage compartment
floor (Y page 303).
X Open the luggage compartment floor
(Y page 303). Vehicles without the ECO start/stop function Vehicles with the ECO start/stop function
X
Pull cover :of the ball coupling recess
upwards in the direction of the arrow and
remove it. Vehicles without the ECO start/stop function
Vehicles with the ECO start/stop function
X
Take ball coupling :with the key from ball
coupling stowage compartment ;.218
Towing a trailerDriving and parking

X
Pull protective cap :down in the direction
of the arrow, out of the ball coupling recess.
X Place protective cap :into the ball cou-
pling recess. X
Pull protective cap ;off the lock in the
handwheel.
X Insert key :into the ignition lock.
The red mark on the handwheel must be
aligned with the green area on the ball cou-
pling (fitting position). If this is not the case:
X Turn key :in the direction of the arrow.
The key is released. X
Pull handwheel ?away from the ball cou-
pling and turn it clockwise until it engages.
The green area on the ball coupling is
aligned with the red mark on the hand-
wheel.
X Insert the ball coupling vertically in the
direction of the arrow into ball coupling
recess =until it engages.
Handwheel ?turns during this process.
Green marking Aon the handwheel is
aligned with the green area on ball coupling
B. X
To lock, turn key :to the stop in the direc-
tion of the arrow.
X Remove key :.
X Press protective cap ;onto the lock.
i You can store the key in the ball coupling
recess in the luggage compartment.
X Attach and engage the cover for the ball
coupling recess in the stowage well under
the luggage compartment floor. X
Fold trailer power socket :down. Towing a trailer
219Driving and parking Z

Coupling up a trailer
G
WARNING
If you uncouple a trailer with an engaged over-
run brake, you could trap your hand between
the vehicle and the trailer drawbar. This poses
a risk of injury.
Do not uncouple a trailer with an engaged
overrun brake.
X Make sure that the transmission is in posi-
tion P.
X Engage the parking brake.
X Position the trailer level behind the vehicle.
X Couple up the trailer.
X Establish the electric connection between
the vehicle and the trailer.
X Check that the trailer lighting system is
working. Uncoupling a trailer
G
WARNING
Vehicles with level control:
If you disconnect the trailer cable, the vehicle
is lowered. This can cause you or others to
become trapped between the vehicle body
and tyres, or underneath the vehicle. This
poses a risk of injury.
Make sure that no-one is in the immediate
vicinity of the wheel arch or underneath the
vehicle when disconnecting the trailer cable.
! Do not disconnect a trailer with an
engaged overrun brake. Otherwise, your
vehicle could be damaged by the rebound-
ing of the overrun brake.
X Make sure that the transmission is in posi-
tion P.
X Engage the parking brake.
X Secure the trailer against rolling away.
X Remove the trailer cable and decouple the
trailer. Removing the ball coupling
X Pull the protective cap off the lock in the
handwheel.
X Use the key to unlock the lock in the hand-
wheel.
X Hold the ball coupling. Pull the handwheel
away from the ball coupling and turn it
clockwise until it engages.
The green area on the ball coupling is
aligned with the red mark on the hand-
wheel.
X Pull the ball coupling downwards to
remove.
X Clean the ball coupling if it is dirty.
Information on cleaning and care of the trailer
tow hitch can be found under (Y page 321). Storing the ball coupling
G
WARNING
Never transport an unsecured ball coupling in
the interior of the vehicle.
Otherwise, vehicle occupants could be
injured by the ball coupling being thrown if
you:
R brake sharply
R change direction suddenly
R have an accident
X Open the stowage well under the luggage
compartment floor.
X Remove the cover from the ball coupling
recess.
X Remove the protective cap from the ball
coupling recess.
X Press the protective cap into the ball cou-
pling recess until it engages.
X Make sure that the protective cap is firmly
in place.
X Store the ball coupling with the key inser-
ted in the ball coupling recess. 220
Towing a trailerDriving and parking

X
Replace the cover of the ball coupling
recess and engage it.
X Fold the trailer power socket upwards. Trailer power supply
When it leaves the factory, your vehicle's
trailer socket is equipped with a permanent
power supply and a power supply that is
switched on via the ignition lock.
The permanent power 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.
! You can connect accessories with a
power rating of up to 240 W to the perma-
nent power supply and with a power rating
of up to 180 W to the power supply that is
switched on via the ignition lock.
The trailer battery may not be charged from
the power supply.
The trailer's permanent power supply is
switched off in the event of low vehicle supply
voltage and after six hours at the latest.
You can find more information about fitting
the trailer electrics at a qualified specialist
workshop.
X To switch the connected power supply
on or off: turn the key in the ignition lock
to position 2or 0respectively. Trailer with 7-pin connector
General notes Trailer with 7-pin connector:
you can con-
nect to the 13-pin socket on the ball coupling
using an adapter or, if necessary, an adapter
cable. Both can be obtained at a qualified
specialist workshop. Fitting the adapter
X
Open the socket cover.
X Insert the plug connector with lug :into
groove ;on the socket. Turn the connec-
tor clockwise as far as possible.
X Let the cover engage.
X If you are using an adapter cable, secure
the cable to the trailer with cable ties.
! Make sure that there is sufficient cable
play so that the cable cannot become
detached when cornering. Towing a trailer
221Driving and parking Z

Safety systems (4-button multifunction steering wheel)
Display messages Possible causes/consequences and
M
MSolutions ABS
ABS
curr. unavail. curr. unavail.
ABS (Anti-lock Braking System), ESP
®
(Electronic Stability Pro-
gram), BAS (Brake Assist), PRE-SAFE ®
, hill start assist and ESP ®
trailer stabilisation are temporarily not available.
The adaptive brake lights may also have failed.
In addition, the ä,åand! warning lamps light up in
the instrument cluster.
Possible causes:
R self-diagnosis is not yet complete.
R the on-board voltage may be insufficient.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely affec-
ted. The braking distance in an emergency braking situation can
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
The danger of skidding and having an accident increases.
X Carefully drive on a suitable stretch of road, making slight steer-
ing movements at a speed 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 a qualified specialist workshop. If the display message is shown and the
äwarning lamp flashes
at the same time, the electronic traction system is deactivated.
Otherwise, the brakes on the drive wheels could overheat.
X Let the brakes cool down until the display message disappears
and the äwarning lamp goes out.
The electronic traction system is active again. Display messages
247On-board computer and displays Z

Display messages Possible causes/consequences and
M
MSolutions ABS
ABS
inoperative
inoperative ABS, ESP
®
, BAS, PRE-SAFE ®
, hill start assist and ESP ®
trailer sta-
bilisation are not available due to a malfunction.
The adaptive brake lights may also have failed.
In addition, the ä,å,!andJ warning lamps light
up in the instrument cluster.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely affec-
ted. The braking distance in an emergency braking situation can
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
The danger of skidding and having an accident increases.
X Drive on carefully.
X Visit a qualified specialist workshop. EBD and ABS EBD and ABS
inoperative inoperative
EBD (electronic brake force distribution), ABS, ESP
®
, BAS, PRE-
SAFE ®
, the HOLD function, hill start assist and ESP ®
trailer stabi-
lisation are unavailable due to a malfunction.
The adaptive brake lights may also have failed.
In addition, the ä,åand! warning lamps light up in
the instrument cluster and a warning tone sounds.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The front and rear wheels could therefore
lock if you brake hard, for example.
The steerability and braking characteristics may be severely affec-
ted. The braking distance in an emergency braking situation can
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
The danger of skidding and having an accident increases.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. J
Release parking Release parking
brake brake You are driving with the parking brake applied. A warning tone also
sounds.
X
Release the parking brake. 248
Display
messagesOn-board computer and displays