towing MERCEDES-BENZ GL-Class 2015 X166 Owner's Guide

R
Highway level is set.
R ADS (Adaptive Damping System) adapts
comfortable damping characteristics to
the current operating and driving condi-
tions.
R 4ETS and the differential lock are adap-
ted for driving on snow-covered roads.
R The automatic transmission selects the
automatic drive program for a comforta-
ble driving style that provides for opti-
mum fuel consumption.
R The soft accelerator pedal curve is selec-
ted, e.g. the accelerator pedal must be
pressed significantly further to acceler-
ate.
R The optimum gear for pulling away is
engaged.
Trailer program Select the trailer program when towing a
trailer. X
Selector wheel 0043 0043engaged: briefly press
selector wheel 0043.
Selector wheel 0043extends.
X To select: turn selector wheel 0043until indi-
cator lamp 0044comes on.
Trailer indicator 0087appears in the multi-
function display.
R Highway level is set.
R ADS (Adaptive Damping System) adapts
comfortable damping characteristics to
the current operating and driving condi-
tions.
R The automatic transmission selects the
automatic drive program for a comforta-
ble driving style that provides for opti-
mum fuel consumption, changing gear at optimum points.
R While pulling away, the differential locks
are engaged. Off-road driving systems
4MATIC (permanent four-wheel drive) If you fail to adapt your driving style, 4MATIC
can neither reduce the risk of accident nor
override the laws of physics. 4MATIC cannot
take account of road, weather and traffic con-
ditions. 4MATIC is only 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.
! Never tow the vehicle with one axle
raised. This may damage the transfer case. Damage of this sort is not covered by the
Mercedes-Benz Limited Warranty. All
wheels must remain either on the ground or
be fully raised. Observe the instructions for
towing the vehicle with all wheels in full
contact with the ground.
! A function or performance test should
only be carried out on a two-axle dyna-
mometer. Before you operate the vehicle
on such a dynamometer, please consult a Driving systems
257Driving and parking Z

R
uphill or downhill gradient in percentage
R on-road/off-road program selected
R condition of the differential lock for the
transfer case
R the LOW RANGE off-road gear is selected
R condition of the LOW RANGE off-road
gear
R the on-road trailer program is selected Towing a trailer
Important safety notes
G
WARNING
Installing an unsuitable ball coupling may
result in overloading of the trailer tow hitch
and the rear axle. This applies especially if the ball coupling in question is longer or angled
differently. This could seriously impair the
driving characteristics and the trailer can
come loose. There is a risk of an accident.
You should only ever install a ball coupling
that has the permissible dimensions and that
is designed to meet your trailer-towing
requirements. Do not modify the ball coupling
or the trailer tow hitch.
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" (Y page 459). G
WARNING
If the ball coupling is not installed correctly or not secured with the bolt provided and the
corresponding spring cotter, the trailer may
come loose. There is a risk of an accident.
Always install and secure the ball coupling as
described. Before every journey, ensure that
the ball coupling is secured with the bolt and
the corresponding spring cotter. G
WARNING
If you rest your foot on the brake pedal while
driving, the braking system can overheat. This increases the stopping distance and can even cause the braking system to fail. There is a
risk of an accident.
Never use the brake pedal as a footrest. Never
depress the brake pedal and the accelerator
pedal at the same time. G
WARNING
When the vehicle/trailer combination begins
to lurch, you could lose control of it. The vehi- cle/trailer combination could even rollover.
There is a risk of an accident.
On no account should you attempt to
straighten up the vehicle/trailer combination
by increasing the speed. Reduce vehicle
speed and do not countersteer. Apply the
brake as necessary.
! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
Please observe the manufacturer's operating instructions for the trailer coupling if a
detachable trailer coupling is used.
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 for the trailer
tow hitch and the trailer
R on the vehicle identification plate
If the values differ, the lowest value applies. 264
Towing a trailerDriving and pa
rking

When towing a trailer, your vehicle's handling
characteristics will be different in comparison with 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 radius
This could impair the handling characteris-
tics.
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. Notes on towing a trailer
General notes R
Do not exceed the legally prescribed max-
imum speed for vehicle/trailer combina-
tions in the relevant country.
This lowers the risk of an accident.
R Only install an approved trailer coupling on
your vehicle.
Further information on availability and on
installation is available from any authorized
Mercedes-Benz Center.
R The bumpers of your vehicle are not suita-
ble for installing detachable trailer cou-
plings.
R Do not install hired trailer couplings or
other detachable trailer couplings on the
bumpers of your vehicle.
R If you no longer need the ball coupling,
remove it from the ball coupling recess.
This will reduce the risk of damage to the
ball coupling.
i When towing a trailer, set the tire pres-
sure on the rear axle of the towing vehicle for a maximum load; see the tire pressure
table in the fuel filler flap (Y
page 427).
Please note that when towing a trailer, PARK-
TRONIC (Y page 225) and Blind Spot Assist
(Y page 245) are only available with limita-
tions, or not at all.
You will find installing dimensions and loads
under "Technical data" (Y page 458).
Driving tips i
Observe the information on ESP ®
trailer
stabilization (Y page 75) and on pulling
away with a trailer (Y page 171).
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 permissible speed is. Observe the
legally prescribed maximum speed in the rel-
evant country.
For certain Mercedes-Benz vehicles, the max- imum permissible rear axle load is increased
when towing a trailer. See "Technical data" to
find out whether this applies to your vehicle
(Y page 459). If you utilize any of the added
maximum rear axle load when towing a trailer, the vehicle/trailer combination may not
exceed a maximum speed of 60 mph
(100 km/h) for reasons concerning the oper-
ating permit. This also applies in countries in
which the permissible maximum speed for
vehicle/trailer combinations is above 60 mph
(100 km/h).
When towing a trailer, your vehicle's handling
characteristics will be different in comparison with when driving without a trailer.
Use the left-hand paddle shifter to shift into a
lower gear in good time on long and steep
downhill gradients.
i This also applies if you have activated
cruise control or DISTRONIC PLUS.
This will use the braking effect of the engine,
so that less braking will be required to main-
tain the speed. This relieves the load on the
brake system and prevents the brakes from Towing a trailer
265Driving and parking Z

overheating and wearing too quickly. If you
need additional braking, depress the brake
pedal repeatedly rather than continuously.
Driving tips If the trailer swings from side to side:
X Do not accelerate.
X Do not counter-steer.
X Brake if necessary.
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, decreases with
increasing altitude. Installing the ball coupling
G
WARNING
If the ball coupling is not correctly installed
and secured, it can come loose during the
journey and endanger other road users. There is a risk of an accident and injury.
Always install and secure the ball coupling as
described. Before every journey, ensure that
the ball coupling is secured with the bolt and
the corresponding spring cotter. G
WARNING
If the ball coupling is not installed correctly or not secured with the bolt provided and the
corresponding spring cotter, the trailer may
come loose. There is a risk of an accident.
Always install and secure the ball coupling as
described. Before every journey, ensure that
the ball coupling is secured with the bolt and
the corresponding spring cotter. G
WARNING
If the ball coupling is not installed and secured
correctly the trailer may come loose. There is
a risk of an accident.
Install and secure the ball coupling as descri-
bed in the ball coupling installation instruc-
tions. Make sure that the ball coupling is
installed and secured correctly before every
journey. Cover cap
X Pull protective cap 0043in the direction of the
arrow, out of the ball coupling recess.
X Place protective cap 0043in the ball coupling
recess. 266
Towing a trailerDriving and parking

Ball coupling recess
Holes in the ball coupling and ball coupling recess
X Insert the ball coupling horizontally into ball
coupling recess 0044in the direction of the
arrow until the holes in ball coupling 0087are
in line with the holes in ball coupling
recess 0085. Bolt
X Slide bolt 0083into the hole in the ball cou-
pling recess and the ball coupling to the
stop. Bolt and spring cotter
X Secure the bolt using spring cotter 0084. Correctly installed and secured ball coupling
X Check the ball coupling, bolt and spring
cotter for correct installation.
If the ball coupling cannot be correctly moun-
ted, remove the ball coupling. Under these
circumstances, the ball coupling must not be used for trailer towing.
If the ball coupling cannot be locked and the
key cannot be removed, remove the ball cou-
pling and clean it. If the ball coupling can still
not be installed (locked) after it has been
cleaned, remove the ball coupling. The trailer tow hitch must then not be used to tow a
trailer, as safe operation cannot be guaran-
teed.
Have the entire trailer tow hitch checked at aqualified specialist workshop. Coupling up a trailer
! Do not connect the trailer's brake system
(if featured) to the hydraulic brake system Towing a trailer
267Driving and parking Z

of the towing vehicle, as the latter is equip-
ped with an anti-lock brake system. Doing
so will result in a loss of function of the
brake systems of both the vehicle and the
trailer.
X Make sure that the automatic transmission
is set to position P.
X Apply the vehicle's electric parking brake.
X Start the engine.
X Vehicles with the AIRMATIC package:
select highway level.
X Vehicles with ADS: set ADS toAUTOor
COMF.
X Switch off the engine.
X Close all doors and the tailgate.
X Couple up the trailer.
X Establish all electrical connections.
X Check that the trailer lighting system is
working.
i Vehicles with the AIRMATIC package:
with a trailer attached, the vehicle will
always remain at highway level. When cou-
pling up a trailer, please observe the fol-
lowing:
R Unless highway level has been set man-
ually, the vehicle is automatically low-
ered to highway level. This is the case if a
speed of 5 mph (8 km/h) is reached.
R High-speed level is not available.
These restrictions apply to all accessories
powered through a connection to the trailer power socket of your vehicle, e.g. a bicycle
carrier.
Observe the maximum permissible trailer
dimensions (width and length).
Most U.S. states and all Canadian provinces
require by law:
R Safety chains between the towing vehicle
and the trailer. The chains should be cross-
wound under the trailer drawbar. They must be fastened to the vehicle's trailer cou-
pling, not to the bumper or the axle. Leave enough play in the chains to make
tight cornering possible.
R A separate brake system for certain types
of trailer.
R A safety switch for braked trailers. Check
the specific legal requirements applicable
to your state.
If the trailer detaches from the towing vehi- cle, the safety switch applies the trailer's
brakes. Towing a trailer
There are numerous legal requirements con-
cerning the towing of a trailer, e.g. speed
restrictions. Make sure that your car/trailer
combination complies with the local regula-
tions: R in your place of residence
R in the location to which you are driving
The police and local authorities can provide
reliable information.
Observe the following when towing a trailer:
R To gain driving experience and to become
accustomed to the new handling charac-
teristics, you should practice the following
in a traffic-free location:
- cornering
- stopping
- backing up
R Before driving, check:
- trailer tow hitch
- safety switch for braked trailers
- safety chains
- electrical connections
- lights
- wheels
R Adjust the exterior mirrors to provide an
unobstructed view of the rear section of the trailer.
R If the trailer has electronically controlled
brakes, pull away carefully. Brake manually 268
Towing a trailerDriving and parking

using the brake controller and check
whether the brakes function correctly.
R Secure any objects on the trailer to prevent
the cargo from slipping when the vehicle is
in motion.
R When you couple up a trailer, check at reg-
ular intervals that the load is firmly secured.If the trailer is equipped with trailer lights
and brakes, check the trailer to ensure that
these are working.
R Bear in mind that the handling will be less
stable when towing a trailer than when driv- ing without one. Avoid sudden steering
movements.
R The vehicle/trailer combination is heavier,
accelerates more slowly, has a decreased
gradient climbing capability and a longer
braking distance.
It is more susceptible to side winds and
requires more careful steering.
R If possible, do not brake suddenly, but
instead depress the brake pedal moder-
ately at first so that the trailer can activate its brakes. Then increase the pressure on
the brake pedal.
R If the automatic transmission repeatedly
shifts between gears on uphill or downhill
gradients, shift to a lower gear using the
left-hand steering wheel paddle shifter.
A lower gear and lower speed reduce the
risk of engine failure.
R When driving downhill, shift to a lower gear
to utilize the engine's braking effect.
Avoid continuous brake application as this
may overheat the vehicle brakes and, if
installed, the trailer brakes.
R If the coolant temperature increases dra-
matically while the air-conditioning system
is switched on, switch off the air-condition-
ing system.
Coolant heat can also be dissipated by
opening the windows and switching the ventilation blower and the interior temper-
ature to the highest level.
R When overtaking, pay particular attention
to the extended length of your vehicle/
trailer combination.
Due to the length of the vehicle/trailer
combination, you require additional road
space in relation to the vehicle you are
overtaking before you can change back to
the original lane. Decoupling a trailer
G
WARNING
If you uncouple a trailer with the overrun
brake engaged, you could trap your hand
between the vehicle and the trailer drawbar.
There is a risk of injury.
Do not uncouple a trailer if the overrun brake is engaged. G
WARNING
Vehicles with level control:
The vehicle is lowered as soon as you discon-
nect the trailer cable. This could result in your limbs or those of other people that are
between the vehicle body and tires or under-
neath the vehicle being trapped. There is a
risk of injury.
Make sure that nobody is in the immediate
vicinity of the wheel housings or under the
vehicle when you disconnect 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 automatic transmission
is set to position P.
X Apply the vehicle's electric parking brake.
X Start the engine.
X Close all doors and the tailgate.
X Apply the trailer's parking brake. Towing a trailer
269Driving and parking Z

X
Detach the trailer cable and decouple the
trailer.
X Switch off the engine. Permissible trailer loads and drawbar
loads
Weight specifications Maximum permissible gross vehicle
weight rating
The gross trailer weight is calculated by add-
ing the weight of the trailer to the weight of
the load and equipment on the trailer.
You will find installing dimensions and loads
under "Technical data" (Y page 458).
Permissible noseweight
You will find installing dimensions and loads
under "Technical data" (Y page 458).
Loading a trailer R
When loading the trailer, make sure that
neither the permissible gross weight of the
trailer nor the gross vehicle weight is
exceeded. The permissible gross vehicle
weight is indicated on the identification
plate on the B-pillar on the driver's side of
the vehicle.
You can find the maximum permissible val-
ues on the type plates of your vehicle and
the trailer. When calculating how much
weight the vehicle and trailer may carry,
pay attention to the respective lowest val-
ues.
R The trailer drawbar load on the ball coupling
must be added to the rear axle load to avoid exceeding the permissible gross axle
weight. The permissible gross vehicle
weight is indicated on the identification
plate on the B-pillar on the driver's side of
the vehicle.
i Mercedes-Benz recommends a trailer
load where the trailer drawbar noseweight accounts for 8% to 15% of the trailer's per-
missible gross weight.
i The weight of additional accessories, pas-
sengers, and cargo reduces the permissi-
ble trailer load and drawbar load for your
vehicle.
Checking the vehicle and trailer weight R
To check that the weights of the towing
vehicle and the trailer comply with the max-
imum permissible values, have the vehicle/
trailer combination (including the driver,
passengers, and cargo with a fully laden
trailer) weighed on a calibrated weigh-
bridge.
R Check the gross axle weight rating of the
front and rear axles, the gross weight of the
trailer and trailer drawbar load. Removing the ball coupling
X Remove the spring cotter.
X Remove the bolt from the ball coupling
recess.
X Remove the ball coupling from the ball cou-
pling recess.
X Clean the ball coupling if it is dirty.
X Stow the ball coupling so that it cannot be
thrown around.
Observe the loading guidelines (Y page 342)
and the safety notes regarding stowage
spaces (Y page 343).
Information on cleaning and care of the trailer tow hitch can be found at (Y page 382). Storing the ball coupling
G
WARNING
Do not carry the ball coupling in the vehicle
interior if it is not secured.
Otherwise, you and others could be injured by the ball coupling being thrown around if you: 270
Towing a trailerDriving an
d parking

R
brake sharply
R change direction suddenly
R are involved in an accident Trailer power supply
! You can connect accessories with a max-
imum power consumption of 240 W to the
permanent power supply.
You must not charge a trailer battery using
the power supply.
The trailer socket of your vehicle is equipped at the factory with a permanent power supply.
The permanent power supply is supplied via
trailer socket pin 4.
The trailer's permanent power supply is
switched off in the event of low vehicle supply
voltage and after six hours at the latest.
A qualified specialist workshop can provide
more information about installing the trailer
electrics. Towing a trailer
271Driving and parking Z

Driving systems
Display messages
Possible causes/consequences and
0050
0050Solutions 00AD
Attention Assist: Attention Assist:
Take a Break! Take a Break! Based on certain criteria, ATTENTION ASSIST has detected fatigue
or a lack of concentration on the part of the driver. A warning tone also sounds.
X If necessary, take a break.
During long journeys, take regular breaks in good time so you get enough rest. 00AD
Attention Assist Attention Assist
Inoperative Inoperative ATTENTION ASSIST is inoperative.
X Visit a qualified specialist workshop. 00C4
Drive More Slowly Drive More Slowly You cannot change the vehicle level. Possible causes are:
R you are driving too fast for the selected vehicle level.
R you are towing a trailer.
R the trailer-coupling socket is being used, e.g. for a bicycle rack.
X Drive more slowly and then select the desired vehicle level
again.
R Vehicles with the ON&OFFROAD package (Y page 214)
R Vehicles with the AIRMATIC package (Y page 221)
X Observe the notes on towing a trailer (Y page 265).00C4
Compressor Compressor
Is
IsCool‐
Cool‐
ing
ing You have selected a higher vehicle level. The compressor first
needs to cool down because of frequent level changes.
X Drive in a manner appropriate for the current vehicle level.
X Make sure that there is sufficient ground clearance.
X Allow the compressor to cool down.
When the compressor has cooled down, the display message
disappears. The vehicle then continues rising to the selected
level. 00C4
ABC Malfunction ABC Malfunction AIRMATIC is malfunctioning.
X
Drive as appropriate for the current vehicle level, but do not
exceed 50 mph (80 km/h).
X Make sure that there is sufficient ground clearance.
X Have the vehicle checked at a qualified specialist workshop. 312
Display
messagesOn-board computer and displays