2016 MERCEDES-BENZ GL-Class Owner's Manual

RUphill or downhill gradient in percentage
ROn-road/off-road program selected
RCondition of the differential lock for the
transfer case
RLOW RANGE off-road gear is selected
RCondition of the LOW RANGE off-road
gear
ROn-road trailer program is selected
Towing a trailer
Important safety notes
GWARNING
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" (
Ypage 458).
GWARNING
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.
GWARNING
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
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:
Rthe permissible trailer drawbar noseweight
Rthe permissible trailer load
Rthe permissible rear axle load of the towing
vehicle
Rthe 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:
Rin the vehicle documents
Ron the identification plates for the trailer
tow hitch and the trailer
Ron 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:
Ris heavier
Ris restricted in its acceleration and gradi-
ent-climbing capability
Rhas an increased braking distance
Ris affected more by strong crosswinds
Rdemands more sensitive steering
Rhas a larger turning radius
Towing a trailer263
Driving and parking
Z

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
The following models cannot be used to tow a
trailer:
RGLE 550 e 4MATIC Sport Utility Vehicle
RDo not exceed the legally prescribed max-
imum speed for vehicle/trailer combina-
tions in the relevant country.
This lowers the risk of an accident.
ROnly install an approved trailer coupling on
your vehicle.
Further information on availability and on
installation is available from any authorized Mercedes-Benz Center.
RThe bumpers of your vehicle are not suita-
ble for installing detachable trailer cou-
plings.
RDo not install hired trailer couplings or
other detachable trailer couplings on the
bumpers of your vehicle.
RIf 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.
When towing a trailer, set the tire pressure on the rear axle of the towing vehicle for the
maximum load. You will find the values in the
tire pressure table in the fuel filler flap of the vehicle (
Ypage 425).
Please note that when towing a trailer, the
following driving systems have limited avail-
ability or are not available at all:
RPARKTRONIC (Ypage 224)
RBlind Spot Assist (Ypage 244)
RActive Lane Keeping Assist (Ypage 251) You will find installing dimensions and loads
under "Technical data" (
Ypage 457).
Driving tips
Observe the information on ESP®trailer sta-
bilization (
Ypage 75) and on pulling away with
a trailer (
Ypage 168).
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
(
Ypage 458). 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 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 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
overheating and wearing too quickly. If you
need additional braking, depress the brake
pedal repeatedly rather than continuously.
264Towing a trailer
Driving and parking

Drivingtips
If th etrailer swings from sid eto side:
XDo no taccelerate.
XDo no tcounter-steer .
XBrakeif necessary.
RMaintain agreater distanc efrom th evehi-
cl e in fron tthan when drivin gwithout a
trailer .
RAvoid braking abruptly. If possible, brake
gentlyat first to allow th etrailer to run on .
Then, increase th ebraking forc erapidly.
RThe values given fo rgradient-climbin g
capabilities from astandstill refer to sea
level. Whe ndrivin gin mountainous areas,
note that th epowe routput of th eengin e
and ,consequently, th evehicle' sgradient-
climbin gcapability, decreases wit h
increasing altitude.
Installing th eball coupling
GWARNING
If th eball couplin gis no tcorrectl yinstalled
and secured, it can come loose durin gth e
journey and endanger other road users. There is aris kof an acciden tand injury.
Always install and secure th eball couplin gas
described .Before every journey, ensur ethat
th eball couplin gis secure dwit hth ebolt and
th ecorrespondin gsprin gcotter.
GWARNING
If th eball couplin gis no tinstalled correctl yor
no tsecure dwit hth ebolt provided and th e
correspondin gsprin gcotter, th etrailer may
come loose. There is aris kof an accident.
Always install and secure th eball couplin gas
described .Before every journey, ensur ethat
th eball couplin gis secure dwit hth ebolt and
th ecorrespondin gsprin gcotter.
GWARNING
If th eball couplin gis no tinstalled and secure d
correctl yth etrailer may come loose. There is
a ris kof an accident.
Install and secure th eball couplin gas descri-
bed in th eball couplin ginstallation instruc -
tions. Mak esur ethat th eball couplin gis
installed and secure dcorrectl ybefor eevery
journey.
XPull protective cap :in th edirection of th e
arrow, out of th eball couplin grecess .
XStow protective cap :so that it canno tbe
thrown around .
Observ eth eloadin gguidelines
(
Ypage 340) and th esafet ynote sregard -
in g stowag espaces (
Ypage 341).
Towing a trailer265
Driving and parking
Z

XInsert the ball coupling horizontally into ballcoupling recess ;in the direction of the
arrow until the holes in ball coupling =are
in line with the holes in ball coupling
recess ?.
XSlide bolt Ainto the hole in the ball cou-
pling recess and the ball coupling to the
stop.
XSecure the bolt using spring cotter B.
XCheck 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 trailertow 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 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 equip-
ped with an anti-lock brake system. Doing
266Towing a trailer
Driving and parking

so will result in a loss of function of the
brake systems of both the vehicle and the
trailer.
XShift the transmission to positionP.
XApply the vehicle's electric parking brake.
XStart the engine.
XVehicles with the AIRMATIC package:
select highway level.
XVehicles with ADS:set ADS toAUTOor
COMF .
XSwitch off the engine.
XClose the doors and tailgate.
XCouple up the trailer.
XEstablish the electrical connection
between the vehicle and the trailer.
XCheck that the trailer lighting system is
working.
iVehicles 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:
RUnless 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.
RHigh-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:
RSafety 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.
RA separate brake system for certain types
of trailer.
RSafety switch for braked trailers. Check the
specific legal requirements applicable to
your state.
If the trailer becomes detached from the
towing vehicle, the safety switch applies
the trailer 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:
Rin your place of residence
Rin the location to which you are driving
The police and local authorities can provide
reliable information.
Observe the following when towing a trailer:
RTo 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
RBefore driving, check:
-trailer tow hitch
-safety switch for braked trailers
-safety chains
-electrical connections
-lights
-wheels
RAdjust the exterior mirrors to provide an
unobstructed view of the rear section of the
trailer.
RIf the trailer has electronically controlled
brakes, pull away carefully. Brake manually
Towing a trailer267
Driving and parking
Z

using the brake controller and check
whether the brakes function correctly.
RSecure any objects on the trailer to prevent
the cargo from slipping when the vehicle is
in motion.
RWhen you couple up a trailer, check at reg-
ular intervals that the load isfirmly secured.
If the trailer isequipped with trailer lights
and brakes, check the trailer to ensure that
these are working.
RBear inmind that the handlin g will be less
stable when towing a trailer than when driv-
ing without one. Avoid sudden steering
movements.
RThe vehicle/trailer combination isheavier,
accelerates more slowly, has a decreased
gradient cli mbing capability and a longer
braking distance.
It is more susceptible to side winds and
requires more careful steering.
RIf possible, do not brake suddenly, but
instead depress the brake pedal moder-
ate lyat first so that the trailer can activate
it s brakes. Then increase the pressure on
the brake pedal.
RIf the automat ictransmission repeatedly
shifts between gears on uphill or downhill
gradients, shift to a lower gear using the
left-hand steering wheel paddleshifter.
A lower gear and lower speed reduce the
risk of engine failure.
RWhen drivingdown hill, shift to a lower gear
to uti lize the engine's braking effect.
Avoid co ntin
uous brake application as this
may overheat the vehicle brakes and, if
instal led,the trailer brakes.
RIfthe coolant temperature increases dra-
matical ly while the air-cond itioning system
is swit ched on, switch off the air-condition-
ing system.
Coolant heat can also bedissipated by
opening the windows and switching the ventilation
blower and the interior temper-
ature to the highest leve l.
RWhen 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
spaceinrelation to the vehicle you are
overtaking before you can change back to
the original lane.
Decoupling a trailer
GWARNIN G
If you uncouple atrailer wit hth eoverrun
brak eengaged ,you could trap your han d
between th evehicl eand th etrailer drawbar.
Ther eis aris kof injury.
Do no tuncouple atrailer if th eoverrun brak e
is engaged .
GWARNING
Vehicles wit hleve lcontrol :
The vehicl eis lowered as soo nas you discon -
nect th etrailer cable. This could result in your
limb sor those of other people that are
between th evehicl ebody and tires or under-
neath th evehicl ebein gtrapped .Ther eis a
ris kof injury.
Mak esure that nobody is in th eimmediat e
vicinity of th ewhee lhousing sor under th e
vehicl ewhen you disconnect th etrailer cable.
!Do not disconnect a trailer with an
engaged overrun brake. Otherwise, your
vehicle could bedamaged bythe rebound-
ing of the overrun brake.
XSh ift the transmission to position P.
XApply the vehicle's electr icparking brake.
XStart the engine.
XClose the doors and tailgate.
XApply the trailer's parking brake.
268Towing a trailer
Driving and parking

XDetach the trailer cable and decouple the
trailer.
XSwitch 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" (
Ypage 457).
Permissible noseweight
You will find installing dimensions and loads
under "Technical data" (
Ypage 457).
Loading a trailer
RWhen 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.
RThe trailer drawbar load on the ball coupling
must be added to the rear axle load to avoidexceeding 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.
iMercedes-Benz recommends a trailer
load where the trailer drawbar noseweight accounts for 8% to 15% of the trailer's per-
missible gross weight.
iThe 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
RTo 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.
RCheck 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
XRemove the spring cotter.
XRemove the bolt from the ball coupling
recess.
XRemove the ball coupling from the ball cou-
pling recess.
XClean the ball coupling if it is dirty.
XStow the ball coupling so that it cannot be
thrown around.
Observe the loading guidelines (
Ypage 340)
and the safety notes regarding stowage
spaces (
Ypage 341).
Information on cleaning and care of the trailer
tow hitch (
Ypage 381).
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.
Towing a trailer269
Driving an d parking
Z

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.
270Towing a trailer
Driving and parking