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328 Operation
Driving instructions
Remove excessive dirt from tires,
wheels, wheel housings, and under-
body.
For instance, after driving in mud, clean
the radiator, chassis, engine, brakes,
and wheels from extreme dirt using a
strong jet of water.
Check tires for possible damage.
Inspect vehicle underbody, oil pan,
brake hoses, etc., as well as vehicle un-
derbody for possible damage.
Check for brush or branches caught in
the underbody.
After continued operation in mud,
sand, water or other dirty conditions
clean the brake discs, wheels, brake
pads and check and clean axle joints.
Conduct a brake test.
Trailer towing Trailer hitch*
Only install a trailer hitch receiver ap-
proved for your vehicle.
For information on availability and in-
stallation, contact an authorized
Mercedes-Benz Light Truck Center.
The bumpers on your vehicle are not
designed for use with clamp-type hitch-
es.
Do not attach rental hitches or other
bumper-type hitches to them.
To reduce the possibility of damage, re-
move the hitch ball adaptor from the
receiver when not in use.
!Brush or branches could increase the possi-
bility of a fire, as well as cut fuel and/or brake
lines, puncture rubber bellows of the axles or
drive shafts.
Warning!G
Failure to use proper equipment and driving
technique can result in a loss of vehicle con-
trol when towing a trailer.
Improper towing or failure to follow the in-
structions in this manual can result in vehi-
cle damage and/or serious personal injury.
Follow the guidelines below carefully to as-
sure safe trailer operation.
Contact an authorized Mercedes-Benz Light
Truck Center should you require an explana-
tion of information contained in this manual.
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329 Operation
Driving instructions
Electrical connections
The vehicle is prewired to accept the
seven-wire harness included in the
Mercedes-Benz approved trailer hitch
receiver kit.
For further information, contact an autho-
rized Mercedes-Benz Light Truck Center.
Vehicle and trailer weights and ratings
Gross Vehicle Weight Rating (GVWR) is
the maximum permissible vehicle weight:
ML 350, ML 550, ML 320 CDI:
6235 lb (2830 kg)
ML 63 AMG:
6400 lb (2900 kg)
Gross Vehicle Weight (GVW):
Comprises weight of vehicle including fuel,
tools, spare wheel, installed accessories,
passengers, cargo and trailer tongue. It
must never exceed the GVWR.Gross Axle Weight Rating (GAWR) is the
maximum permissible axle weight:
The Gross Trailer Weight (GTW) is the
weight of the trailer plus the weight of all
cargo, equipment, luggage etc. loaded on
the trailer. The maximum permissible
gross trailer weight to be towed:
7200 lb (3265 kg)
Trailer Tongue Weight Rating (TWR) is the
maximum permissible weight on the trailer
tongue:
576 lb (261 kg) limit for Mercedes-Benz
approved hitch receiver.Loading a trailer
When loading a trailer, you should ob-
serve that neither the permissible GTW,
nor the GVWR are exceeded.
Maximum permissible values are listed
on the safety compliance certification
labels for the vehicle and for the trailer
to be towed.
The lowest value listed must be select-
ed when determining how the vehicle
and trailer are loaded.
The tongue weight at the hitch ball
must be added to the GVW to prevent
exceeding your Mercedes-Benz tow
vehicle’s rear GAWR.
iA four-pole conversion plug is available from
your authorized Mercedes-Benz Light Truck
Center as a spare part.
ML 320 CDI
ML 350
ML 550
Front3085 lb (1400 kg)
Rear3525 lb (1600 kg)
ML 63 AMG
Front3180 lb (1440 kg)
Rear3525 lb (1600 kg)
iWe recommend loading the trailer in such a
manner that it has a Tongue Weight (TW)
between 8% and 15% of the Gross Trailer Weight
(GTW).
iMaximum trailer weight ratings are calculat-
ed assuming the vehicle, plus driver. The weight
of other accessories, passengers and cargo will
reduce the maximum trailer weight and Tongue
Weight (TW) your vehicle can tow.
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330 Operation
Driving instructions
Checking weights of vehicle and trailer
To assure that the tow vehicle and trail-
er are in compliance with the maximum
permissible weight limits have the load-
ed rig (tow vehicle including driver, pas-
sengers and cargo, trailer fully loaded)
weighed on a commercial scale.
Check the vehicle’s front and rear
Gross Axle Weight (GAW), the Gross
Trailer Weight (GTW) and Tongue
Weight (TW).
The values as measures must not
exceed the weight limits listed under
“Vehicle and trailer weight and ratings”
(
page 329).Attaching a trailerObserve maximum permitted trailer
dimensions (width and length).
Most states and all Canadian provinces
require
safety chains between your tow vehicle
and the trailer.
The chains should be criss-crossed
under the trailer tongue. They must be
attached to the hitch receiver, and not
to the vehicle’s bumper or axle.
Make sure to leave enough slack in the
chains to permit turning corners.
a separate brake system at various
trailer weights.
a break-away switch on trailers with a
separate brake system. Check with
your local state laws for specific
requirements.
The switch activates the trailer brakes
in the possible event that the trailer
might separate from the tow vehicle.
Warning!G
Vehicles with air suspension program*:
While you are coupling or decoupling a
trailer, make sure that you do not
lock or unlock
open or close
a vehicle door or the tailgate.
The vehicle’s level could change and you
could endanger yourself and/or others as a
result.
Make sure that you do not operate the ADS
button* (
page 255) or the vehicle level
control system* (
page 255) when cou-
pling/decoupling the trailer.
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331 Operation
Driving instructions
Make sure the automatic transmission
is set toP (
page 185).
Set the parking brake for the vehicle
(
page 65).
Start the engine (page 54).
Vehicles with air suspension program*:
Set the vehicle level to Highway
(
page 255).
Vehicles with air suspension program*:
Set the ADS* to AUTO or COMFORT
(
page 255).
Turn off the engine (page 66).
Close all doors and the tailgate.
Attach the trailer.
Plug in all electrical connectors.Towing a trailer
There are many different laws, including
speed limit restrictions, having to do with
trailer towing. Make sure your rig will be le-
gal, not only for where you reside, but also
for where you will be driving. A good
source for this information can be the po-
lice or local authorities.
Note the following points, when driving
with the trailer:
In order to gain skill and an understand-
ing of the vehicle’s behavior, you
should practice turning, stopping and
backing up in an area which is free from
traffic.
Before you start driving check the
trailer hitch
break-away switch
safety chains
electrical connections
lighting and tires
!Do not connect a trailer brake system (if
trailer is so equipped) directly to the vehicle’s
hydraulic brake system, as your vehicle is
equipped with antilock brakes. If you do, neither
the vehicle’s brakes nor the trailer’s brakes will
function properly.
iThe provided vehicle electrical wiring
harness for trailer towing has a brake signal wire
for hook-up to a brake controller.
You should consider using a trailer sway control
system. For further information, contact an
authorized Mercedes-Benz Light Truck Center.
iVehicles with air suspension program*:
When you are towing a trailer, the vehicle level
always remains in the Highway setting.
The following applies additionally when towing a
trailer:
The vehicle is lowered to the highway level
when it reaches a speed of 5 mph (8 km/h)
if not set to highway level.
The high-speed level is not available.
The restrictions that apply to towing also apply
when using accessories that are connected to
the trailer power socket, such as a bicycle rack.
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332 Operation
Driving instructions
Adjust the mirrors (page 49) to
permit unobstructed view beyond rear
of trailer.
If the trailer has electric brakes, start
your vehicle and trailer moving slowly,
and then apply only the trailer brake
controller by hand to make sure the
brakes are working properly.
Always secure items in the trailer to
prevent load shifts while driving.
When towing a trailer, check occasion-
ally to make sure the load is secure,
and that lighting and trailer brakes (if
so equipped) are functioning properly.
Take into consideration that when tow-
ing a trailer, the handling characteris-
tics are different and less stable from
those when operating the vehicle with-
out a trailer.
It is important to avoid sudden maneu-
vers.
The vehicle and trailer combination is
heavier, and therefore is limited in ac-
celeration and climbing ability, and re-
quires longer stopping distances.
It is more prone to reacting to cross
wind gusts, and requires more sensi-
tive steering input.
If possible, do not brake abruptly, but
rather engage the brake slightly at first
to permit the trailer to activate its
brake. Then increase the braking force.
If the transmission repeatedly shifts
between gears on inclines, manually
shift to a lower gear (select 4, 3, 2 or 1)
(
page 192).
A lower gear and reduction of speed re-
duces the chance of engine overload-
ing and/or overheating.
On very steep inclines, not manageable
with automatic transmission in1,
switch on off-road driving program
(
page 253).
When going down a long hill, shift into
a lower gear and use the engine’s brak-
ing effect.
Avoid riding the brakes, thus overheat-
ing the vehicle and trailer brakes.
If the engine coolant rises to an ex-
tremely high temperature (coolant tem-
perature needle approaching the red
zone) when the air conditioning is on,
turn off the air conditioning system.
Engine coolant heat can be additionally
vented by opening the windows,
switching the climate control fan speed
to high and setting the temperature
control to the maximum hot position.
!If the trailer should begin to sway, reduce
the vehicle’s speed immediately.
In no case attempt to straighten out the tow
vehicle and trailer by increasing the speed.
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333 Operation
Driving instructions
Extreme care must be exercised since
your vehicle with a trailer will require
additional passing distance ahead than
when driving without a trailer.
Because your vehicle and trailer is
longer than your vehicle alone, you will
also need to go much farther ahead of
the passed vehicle before you can re-
turn to your lane.
Uncoupling the trailer
Make sure the automatic transmission
is set toP (
page 185).
Set the parking brake for the vehicle
(
page 65).
Start the engine (page 54).
Close all doors and the tailgate.
Set the parking brake for the trailer.
Disconnect all electrical plug connec-
tors.
Uncouple the trailer.
Make sure that the trailer coupling is
free of load.
Turn off the engine (page 66).
Warning!G
Vehicles with air suspension program*:
While you are coupling or decoupling a trail-
er, make sure that you do not
lock or unlock
open or close
a vehicle door or the tailgate.
The vehicle’s level could change and you
could endanger yourself and/or others as a
result.
Make sure that you do not operate the ADS
button* (
page 255) or the vehicle level
control system* (
page 255) when cou-
pling/decoupling the trailer.
Warning!G
Vehicles with air suspension program*:
As soon as you disconnect the electrical
connection between the trailer and the
vehicle, the vehicle will lower. To help avoid
personal injury, make sure no one is near
the wheel housing or underneath the vehicle
before the electrical connection is discon-
nected.
When you uncouple the trailer, the vehicle is
temporarily raised because the springs are
relieved of load. Be especially careful during
this process, as you could otherwise injure
yourself and/or others. Make sure that any
persons remaining in the vehicle do not
press the switches for vehicle level control
or the ADS*.
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334 Operation
Driving instructions
Passenger compartmentDriving abroad
Abroad, there is an extensive
Mercedes-Benz service network at your
disposal. If you plan to drive into areas
which are not listed in the index of your
Mercedes-Benz Light Truck Center
directory, you should request pertinent
information from an authorized
Mercedes-Benz Light Truck Center.
Control and operation of radio
transmitters
COMAND system, radio and telephone*Telephones and two-way radios
Radio transmitters, such as a portable
telephone or a citizens band unit should
only be used inside the vehicle if they are
connected to an antenna that is installed
on the outside of the vehicle.
Warning!G
Always fasten items being carried as secure-
ly as possible.
In an accident, during hard braking or sud-
den maneuvers, loose items will be thrown
around inside the vehicle, and cause injury
to vehicle occupants unless the items are
securely fastened in the vehicle.
The rear cargo compartment is the preferred
place to carry objects. Always use tie down
rings, and if so equipped, always use the
cargo net* when transporting cargo. The
cargo net* cannot secure hard or heavy ob-
jects. Always fasten items being carried as
securely as possible using the cargo
tie-down rings in the cargo floor area and
fastening materials.
Warning!G
Do not forget that your primary responsibili-
ty is to drive the vehicle. Only operate the
COMAND system, radio or telephone
1 if
road, weather and traffic conditions permit.
1Observe all legal requirements.
Bear in mind that at a speed of just 30 mph
(approximately 50 km/h), your vehicle is
covering a distance of 44 feet (approximate-
ly 14 m) every second.
Warning!G
Never operate radio transmitters equipped
with a built-in or attached antenna (i.e. with-
out being connected to an external antenna)
from inside the vehicle while the engine is
running. Doing so could lead to a malfunc-
tion of the vehicle’s electronic system,
possibly resulting in an accident and/or
personal injury.
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335 Operation
Driving instructions
Refer to the radio transmitter operation
instructions regarding use of an external
antenna.
Catalytic converter (gasoline engine)
Your Mercedes-Benz is equipped with
monolithic-type catalytic converters, an
important element in conjunction with the
oxygen sensors to achieve substantial con-
trol of the pollutants in the exhaust emis-
sions. Keep your vehicle in proper
operating condition by following our rec-
ommended maintenance instructions as
outlined in your Maintenance Booklet.
Oxidation catalyst (diesel engine)
Your vehicle is equipped with an oxidation
catalyst, an important element in conjunc-
tion with the oxygen sensors to achieve
substantial control of the pollutants in the
exhaust emissions. Keep your vehicle in
proper operating condition by following
our recommended maintenance instruc-
tions as outlined in your Maintenance
Booklet.Emission control
Certain engine systems serve to keep the
toxic components of the exhaust gases
within permissible limits required by law.
These systems, of course, will function
properly only when maintained strictly ac-
cording to factory specifications. Any ad-
justments on the engine should, therefore,
be carried out only by qualified
Mercedes-Benz Light Truck Center autho-
rized technicians.
!To prevent damage to the catalytic convert-
ers, use only premium unleaded gasoline in this
vehicle.
Any noticeable irregularities in engine operation
should be repaired promptly. Otherwise, exces-
sive unburned fuel may reach the catalytic con-
verter, causing it to overheat and potentially
start a fire.
Warning!G
As with any vehicle, do not idle, park or op-
erate this vehicle in areas where combusti-
ble materials such as grass, hay or leaves
can come into contact with the hot exhaust
system, as these materials could be ignited
and cause a vehicle fire.
Warning!G
As with any vehicle, do not idle, park or op-
erate this vehicle in areas where combusti-
ble materials such as grass, hay or leaves
can come into contact with the hot exhaust
system, as these materials could be ignited
and cause a vehicle fire.