trailer MERCEDES-BENZ GLS 2019 Owner's Guide

R
you switch on the turn signals. In this event,
the warnings are suppressed for a certain
period of time.
R a driving safety system intervenes, such as
ABS, BAS or ESP ®
.
When Adaptive
Adaptive is selected, no warning vibra-
tion occurs if:
R you switch on the turn signals. In this event,
the warnings are suppressed for a certain
period of time.
R a driving safety system intervenes, e.g.
ABS, BAS or ESP ®
.
R you accelerate hard, e.g. kickdown.
R you brake hard.
R you steer actively, e.g. swerve to avoid an
obstacle or change lanes quickly.
R you cut the corner on a sharp bend.
Towing a trailer
When you attach a trailer, make sure you have
correctly established the electrical connection.
This can be accomplished by checking the trailer
lighting. Lane-correcting brake application does not take place when towing a trailer. Active Lane
Keeping Assist is not activated and the lines in
the assistance graphic are gray. Off-road driving systems
4MATIC (permanent four-wheel drive) 4MATIC ensures that all four wheels are perma-
nently driven. Together with ESP ®
and 4ETS, it
improves the traction of your vehicle whenever
a drive wheel spins due to insufficient grip.
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 conditions. 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 vehi-
cle with all wheels in full contact with the
ground. !
A function or performance test should only
be carried out on a two-axle dynamometer.
Before you operate the vehicle on such a
dynamometer, please consult a qualified
workshop. You could otherwise damage the
drive train or the brake system.
i In wintry driving conditions, the maximum
effect of 4MATIC can only be achieved if you
use winter tires (M+S tires), with snow chains
if necessary.
Further information about "Driving off-road"
(Y page 166).
DSR (Downhill Speed Regulation) General notes
DSR is an aid to assist you when driving down-
hill. It keeps the speed of travel at the speed
selected on the on-board computer. The steeper
the downhill gradient, the greater the DSR brak- ing effect on the vehicle. When driving on flat
stretches of road or on an uphill gradient, the
DSR braking effect is minimal or nonexistent.
DSR controls the vehicle’s speed when it is acti-
vated and the transmission is in position 005B,005E
or 005C. You can drive at a higher or a lower speed
than that set on the on-board computer at any
time by accelerating or braking.
Important safety notes G
WARNING
If the speed driven and the set speed deviate and you activate DSR on a slippery road sur-
face, the wheels may lose traction. There is an
increased danger of skidding and accidents.
Before switching DSR on, please take into
consideration the road surface and the differ- ence between driving speed and the set
speed.
If you fail to adapt your driving style, DSR can
neither reduce the risk of accident nor override the laws of physics. DSR cannot take account of
road, weather and traffic conditions. DSR is only
an aid. You are responsible for the distance to
the vehicle in front, for vehicle speed, for brak-
ing in good time and for staying in your lane.
You are always responsible for keeping control
of the vehicle and for assessing whether the
downhill gradient can be managed. DSR may not always be able to keep to the set speed, depend- Driving systems
215Driving and parking Z

006D
Level control
006E Compass with angle scale
Activating the driving dynamics display X
Switch on COMAND (see the Digital Opera-
tor's Manual).
X Press button 0043.
The driving dynamics display appears in the
COMAND display. Towing a trailer
Important safety notes
G
WARNING
Installing an unsuitable ball coupling may
overload the trailer tow hitch and the rear
axle. This is particularly likely in the case of
longer or differently angled ball couplings.
Consequently, the driving characteristics may
be significantly impaired and the trailer may
detach. This presents the risk of an accident
or even fatal injuries!
Install only a ball coupling that adheres to the permissible dimensions and is designed for
your intended purpose for towing a trailer. Do
not make any changes to the ball coupling or the trailer tow hitch.
You will find the values approved by the manu-
facturer on the vehicle identification plates and
those for the towing vehicle under "Technical
data" (Y page 392). 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
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.
Please observe the manufacturer's operating
instructions for the trailer coupling if a detach-
able 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.
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 gradient-
climbing capability
R has an increased braking distance Towing a trailer
221Driving and parking Z

R
is affected more by strong crosswinds
R demands more sensitive steering
R has a larger turning circle
This could impair the handling characteristics.
When towing a trailer, always adjust your speed to the current road and weather conditions. Do
not exceed the maximum permissible speed for
your vehicle/trailer combination. Notes on towing a trailer
General notes !
If you have a trailer tow hitch retrofitted,
changes to the cooling system and drive train may be necessary, depending on the vehicle
type.
If you have a trailer tow hitch retrofitted,
observe the anchorage points on the chassis
frame.
R Do not exceed the legally prescribed maxi-
mum speed for vehicle/trailer combinations
in the relevant country.
This lowers the risk of an accident.
R Only install an approved trailer coupling on
your vehicle.
More information on availability and installa-
tion can be obtained at any qualified special-
ist workshop.
R The bumpers of your vehicle are not suitable
for installing detachable trailer couplings.
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 cou-
pling.
When towing a trailer, set the tire pressure on
the rear axle of the towing vehicle for the max-
imum load. You will find the values in the tire
pressure table in the fuel filler flap of the vehicle (Y page 371).
Please note that when towing a trailer, the fol-
lowing driving systems have limited availability
or are not available at all:
R Parking Assist PARKTRONIC (Y page 189)
R Blind Spot Assist (Y page 207)
R Active Lane Keeping Assist (Y page 212)On vehicles without level control, the height of
the ball coupling will alter according to the load
placed on the vehicle. If necessary, use a trailer
with a height-adjustable drawbar.
You will find installing dimensions and loads
under "Technical data" (Y page 392).
Driving tips Also observe the notes on pulling away with a
trailer (Y
page 143).
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 maximum
permissible speed is for your trailer. Observe the
legally permissible maximum speed in the rele-
vant country.
For certain Mercedes-Benz vehicles, the maxi-
mum permissible rear axle load is increased
when towing a trailer. See "Technical data" to
find out whether this applies to your vehicle
(Y page 392). 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 operating permit. This
also applies in countries in which the maximum
permissible speed for car/trailer combinations
is greater than 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 steering wheel paddle shifter
to shift into a lower gear in good time on long
and steep downhill gradients.
This also applies if you have activated cruise
control or Active Distance Assist DISTRONIC.
This will use the braking effect of the engine, so that less braking will be required to maintain the
speed. This relieves the load on the brake sys-
tem 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 If the trailer swings from side to side:
X Do not accelerate.
X Do not counter-steer.
X Brake if necessary. 222
Towing a trailerDriving and parking

R
Maintain a greater distance from the vehicle
in front than when driving without a trailer.
R Avoid braking abruptly. If possible, brake gen-
tly at first to allow the trailer to run on. Then,
increase the braking force rapidly.
R The values given for gradient-climbing capa-
bilities from a standstill refer to sea level.
When driving in mountainous areas, note that
the power output of the engine and, conse-
quently, the vehicle's gradient-climbing capa- bility, 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. X
Pull protective cap 0043in the direction of the
arrow, out of the ball coupling recess.
X Stow protective cap 0043so that it cannot be
thrown around.
Observe the loading guidelines (Y page 295)
and the safety notes regarding stowage
spaces (Y page 295). 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. Towing a trailer
223Driving and parking Z

X
Slide bolt 0083into the hole in the ball coupling
recess and the ball coupling to the stop. X
Secure the bolt using spring cotter 0084.X
Check the ball coupling, bolt and spring cotter
for correct installation.
If the ball coupling cannot be correctly mounted,
remove the ball coupling. Under these circum-
stances, the ball coupling must not be used for
trailer towing.
Have the entire trailer tow hitch checked at a
qualified specialist workshop. Coupling up a trailer
! Do not connect the trailer's brake system (if
featured) to the hydraulic brake system of the towing vehicle, as the latter is equipped 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 Shift the transmission to position 005D.
X Apply the vehicle's electric parking brake.
X Start the engine.
X Vehicles with AIRMATIC Package: select
normal level and the Comfortdrive program.
X Switch off the engine.
X Close the doors and tailgate.
X Couple up the trailer.
X Establish the electrical connection between
the vehicle and the trailer.
X Check that the trailer lighting system is work-
ing.
X Push the combination switch upwards/down-
wards and check whether the corresponding
turn signal on the trailer flashes.
A trailer that is connected is recognized only
when the electrical connection is established
correctly and when the lighting system is work-
ing properly. The function of other systems also depends on this, for example:
R ESP ®
R Parking Assist PARKTRONIC
R Active Parking Assist
R Parking Package with rear view camera
R Active Blind Spot Assist
R Active Lane Keeping Assist
i Vehicles with the AIRMATIC Package: if you
couple up a trailer, the vehicle always remains
at normal level. When coupling up a trailer,
please observe the following:
R If the normal level has not been set man-
ually, the vehicle is automatically lowered
to normal level. This is the case if a speed of
5 mph (8 km/h) is reached.
R The Sport drive program 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). 224
Towing a trailerDriving and parking

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-woundunder the trailer drawbar. They must be fas-
tened to the vehicle's trailer coupling, 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 Safety switch for braked trailers. Check the
specific legal requirements applicable to your
state.
If the trailer becomes detached from the tow-
ing vehicle, the safety feature triggers the
trailer brakes. Towing a trailer
There are numerous legal requirements con-
cerning the towing of a trailer, e.g. speed restric-
tions. Make sure that your car/trailer combina- tion complies with the local regulations:
R in your place of residence
R in the location to which you are driving
The police and local authorities can provide reli-
able information.
Observe the following when towing a trailer:
R To gain driving experience and to become
accustomed to the new handling characteris-
tics, 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 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 regular
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 driving
without one. Avoid sudden steering move-
ments.
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 moderately at first sothat 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 gra-
dients, 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 instal- led, the trailer brakes.
R If the coolant temperature increases dramat-
ically while the air-conditioning system is
switched on, switch off the air-conditioning
system.
Coolant heat can also be dissipated by open-
ing the windows and switching the ventilation blower and the interior temperature 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 com-
bination, you require additional road space in
relation to the vehicle you are overtaking
before you can change back to the original
lane. Towing a trailer
225Driving and parking Z

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 rebounding of the overrun
brake.
X Shift the transmission to position 005D.
X Apply the vehicle's electric parking brake.
X Start the engine.
X Close the doors and tailgate.
X Apply the trailer's parking brake.
X Detach the trailer cable and decouple the
trailer.
X Switch off the engine. Permissible trailer loads and drawbar
loads
Weight specifications Maximum allowable gross mass
The gross vehicle weight of the trailer is calcu-
lated by adding 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 392).Permissible noseweight
You will find installing dimensions and loads
under "Technical data" (Y page 392).
Loading a trailer R
When loading the trailer, make sure that nei-
ther the permissible gross weight of the trailer
nor the gross vehicle weight are exceeded.
The permissible gross vehicle weight is indi-
cated on the identification plate located on
the B-pillar on the driver's side of the vehicle.
You can find the maximum permissible values
on the type plates of your vehicle and the
trailer. When calculating how much weight
the vehicle and trailer may carry, pay atten-
tion to the respective lowest values.
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 indi-
cated on the identification plate located 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 permissible
trailer load and drawbar load for your vehicle.
Checking the vehicle and trailer weight R
To check that the weights of the towing vehi-
cle and the trailer comply with the maximum
permissible values, have the vehicle/trailer
combination (including the driver, passen-
gers, and cargo with a fully laden trailer)
weighed on a calibrated weighbridge.
R Check the gross axle weight rating of the front
and rear axles, the gross weight of the trailer
and the trailer drawbar noseweight. 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. 226
Towing a trailerDriving and pa
rking

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 295)
and the safety notes regarding stowage spaces
(Y page 295).
Information on cleaning and care of the trailer
tow hitch (Y page 331). Trailer power supply
! Accessories with a maximum power con-
sumption of 180 W can be connected 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. Bicycle rack
General notes
Trailer tow hitch (example with additional
guide pin) Depending on the bicycle rack's design, you can
transport up to four bicycles on it:
R When attached by clamping onto ball cou-
pling 0043, the maximum payload is 75 kg. You
can transport up to three bicycles.
R When attached to ball coupling 0043and also
guide pin 0044, the maximum payload is 100 kg.
You can transport up to three bicycles.
The payload is calculated from the weight of the
bicycle rack and the load of the bicycle rack.
To transport bicycles with a gross weight
between 75 kg and 100 kg, use only bicycle
racks with additional anchorage on guide pin 0044. Important safety notes
G
WARNING
The bicycle rack can detach from the vehicle if
you
R exceed the permissible payload of the
trailer tow hitch
R use the bicycle rack incorrectly
R attach the bicycle rack to the ball coupling
beneath the ball head
There is a risk of an accident.
For your safety and that of other road users,
observe the following:
R Always observe the permissible payload of
the trailer tow hitch.
R Use the bicycle rack only to transport bicy-
cles.
R Always attach the bicycle rack correctly by
clamping onto the ball head and, if possible, to the guide pin on the ball coupling as well.
R To transport four bicycles, always use bicy-
cle racks with additional support on the ball
coupling's guide pin.
R Use only bicycle racks approved by
Mercedes-Benz.
R Always comply with the bicycle rack's oper-
ating manual.
! Using unsuitable bicycle racks or using
them incorrectly can cause damage to and
fractures in the trailer tow hitch. Bicycle rack
227Driving and parking Z

Use only bicycle racks approved by
Mercedes-Benz.
Bicycle racks cause your vehicle's driving char-
acteristics to change. The vehicle: R is heavier
R is restricted in its acceleration and gradient-
climbing capability
R has an increased braking distance This could impair the handling characteristics.
Adapt your driving style accordingly. Maintain a
safe distance and drive carefully.
When using bicycle racks, set the tire pressure
on the rear axle of the vehicle for the maximum
load. Further information on tire pressure can be
found on the tire pressure table (Y page 355).Loading instructions
The greater the distance between the load's center of gravity and the ball head, the higher the load exerted on the trailer tow hitch.
Therefore, observe the following notes:
R Attach heavy bicycles as close as possible to the vehicle.
R Always distribute the load on the bicycle rack as symmetrically as possible to the vehicle longi-
tudinal axis.
Before loading the bicycle rack, Mercedes-Benz advises you to remove all add-on parts from the
bicycles, e.g. bicycle baskets, child seats or batteries. This will allow you to improve the aerody-
namic resistance and the bicycle rack's center of gravity.
Always secure bicycles against slipping and check that they are firmly seated at regular intervals.
Do not use tarpaulins or other covers. This could impair the driving characteristics and rear visibility. The aerodynamic resistance would also rise, and so would the load exerted on the trailer tow hitchas a result. Load distribution on the bicycle rack
0043 Distance in height between the center of gravity and the ball coupling
0044 Distance to the rear between the center of gravity and the ball coupling
0087 The center of gravity is located on the central axis of the vehicle 228
Bicycle rackDriving and parking

When loading the bicycle rack, comply with the following notes:
Number of bicycles Gross weight of bicy-
cle rack and load Max. distance
0043
0043 Max. distance
0044
0044 3 up to 75 kg 420 mm 300 mm
4
2 up to 100 kg
2 420 mm 400 mm
Notes on towing vehicles
The vehicle is not suitable for attaching tow bar
systems, such as those used for flat towing or
dinghy towing.
Attaching or using tow bar systems may result in
damage to the vehicle.
When towing a vehicle with tow bar systems,
safe driving characteristics cannot be guaran-
teed for the towing vehicle or the towed vehicle.
The vehicle/vehicle combination may swerve.
Observe the permissible towing methods
(Y page 347) and the notes on towing with both
axles on the ground (Y page 347).
2 When transporting four bicycles or a gross weight between 75 kg and 100 kg, use only bicycle racks with
additional support on the guide pin of the trailer tow hitch. Notes on towing vehicles
229Driving and parking Z