1997 MERCEDES-BENZ ML350 trailer

191
Driving instructions
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
Electrical connections
The vehicle is prewired to accept the seven-wire harness
included in the Mercedes-Benz approved trailer hitch
receiver kit. An additional four-pole conversion plug is
included in the Mercedes-Benz supplied trailer hitch
receiver kit. For further information, please see your
authorized Mercedes-Benz Light Truck Center.
In order to prevent possible damage to the vehicle’s
electrical system by incorrectly installing the trailer
wiring plug, we recommend having the harness
connected at an authorized Mercedes-Benz Light Truck
Center. Vehicle and trailer weights and ratings
Gross Vehicle Weight Rating (GVWR) is the maximum
permissible vehicle weight: 6005 lbs. (2724 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:
Gross Trailer Weight (GTW) is the maximum
permissible trailer weight to be towed:
5000 lbs. (2260 kg)
Trailer Tongue Weight Rating (TWR) is the maximum
permissible weight of the trailer tongue:
[500 lbs. (225 kg) limit for MB approved hitch receiver]
front
rear 2755 lbs.
3527 lbs. (1250 kg)
(1600 kg)

192
Driving instructions
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
Loading a trailer
When loading a trailer, you should observe 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
selected when determining how the vehicle and trailer
are loaded.
We recommend loading the trailer in such a manner
that it has a tongue weight (TW) between 10% and 15%
of the GTW.
The tongue weight at the hitch ball must be added to the
GVW to prevent exceeding your Mercedes-Benz tow
vehicle’s rear GAWR. Checking weights of vehicle and trailer
To assure that the tow vehicle and trailer are in
compliance with the maximum permissible weight
limits, and to know the actual weights, have the loaded
rig (tow vehicle including driver, passengers and cargo,
trailer fully loaded) weighed on a commercial scale.
Check the vehicle’s front and rear Gross Axle Weight
(GAW), the GTW and TW. The values as measured must
not be exceeded, according to the weight listed under
“Vehicle and trailer weight and ratings”.

193
Driving instructions
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
Attaching a trailer
Please observe 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 crisscrossed under the trailer tongue.
They must be attached to the hitch receiver, and not to
the vehicle’s bumper or axle. Be sure to leave enough
slack in the chains to permit turning corners.
Most states and all Canadian provinces require a
separate brake system at various trailer weights. Caution!
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.
The provided vehicle electrical wiring harness for trailer
towing has a brake signal wire (color orange) for
hook-up to a brake controller.
Most states and all Canadian provinces require a
break-away switch on trailers with a separate brake
system. The switch activates the trailer brakes in the
possible event that the trailer might separate from the
tow vehicle.
You should consider using a trailer sway control system.
For further information see your authorized
Mercedes-Benz Light Truck Center.

194
Driving instructions
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
Tow in g a t r ai le r
There are many different laws, including speed limit
restrictions, having to do with trailer towing. Make sure
t ha t your rig will be lega l, not only for w here you reside,
but also for where you will be driving. A good source for
this information can be the police or local authorities.
Before you start driving with the trailer, check the
trailer hitch, break-away switch, safety chains, electrical
connections, lighting and tires. Also adjust the mirrors
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 be sure the brakes are
working properly.
When towing a trailer, check occasionally to be sure that
the load is secure, and that lighting and trailer brakes
(if so equipped) are functioning properly.
Always secure items in the trailer to prevent load shifts
while driving.
Take into consideration that when towing a trailer, the
handling characteristics are different and less stable
from those when operating the vehicle without a trailer.
It is important to avoid sudden maneuvers. The vehicle and trailer combination is heavier, and
therefore is limited in acceleration and climbing ability,
and requires longer stopping distances. It is more prone
to reacting to side wind gusts, and requires more
sensitive steering input.
In order to gain skill and an understanding of the
vehicle’s behavior, you should practice turning,
stopping and backing up in an area which is free from
traffic.
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.
Caution!
If the trailer should begin to sway, reduce the vehicle’s
speed and use the brake controller by hand to straighten
out the vehicle and trailer. In no case should you
attempt to straighten out the tow vehicle and trailer by
increasing the speed or oversteering and stepping on
the brakes.
If the transmission hunts between gears on inclines,
manually shift to a lower gear (select “4”, “3”, “2”
or “1”). A lower gear and reduction of speed reduces the
chance of engine overloading and / or overheating.

195
Driving instructions
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
At very steep inclines, not manageable with selector
lever in position “1”, switch transfer case to LOW
RANGE, see page 209 for instructions on how to engage
LOW RANGE.
When going down a long hill, shift into a lower gear and
use the engine’s braking effect. Avoid riding the brakes,
thus overheating the vehicle and trailer brakes.
If the engine coolant rises to an extremely high
temperature (coolant temperature needle approaching
the red zone) when the air conditioner is on, turn off the
air conditioner. 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.
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 return to your lane. Parking
Wa r n i n g !
To reduce the risk of personal injury, or damage to
the vehicle powertrain, as a result of vehicle/trailer
movement, always:1. Keep right foot on brake pedal.2. Shift gear selector lever to position “N”.3. Have a second person place wheel chocks on
downhill side of left and right trailer wheels.4. Slowly release brake pedal and let vehicle and trailer roll into chocks until stopped.5. Firmly depress parking brake pedal.6. Move gear selector lever to position “P”.7. On inclines turn front wheels towards the road curb.

198
Driving systems
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
Notes:
If the engine does not brake the vehicle sufficiently
while driving on a downgrade, the speed you set on the
cruise control may be exceeded. In this case the
automatic transmission shifts down (max. to 3rd gear)
to maintain the set cruise control speed by using the
engine’s braking power.
As soon as the grade eases, the automatic transmission
shifts up again dependent on the selector lever position.
Nevertheless, in some cases you may have to step on the
b ra ke pe dal to slow d own. In t his case t he cruise control
is switched off.
Use the lever to resume the previously set speed. Transmission in LOW RANGE mode
The cruise control should not be activated during off-
road driving in the LOW RANGE mode. Doing so could
reduce driving comfort.
Trailer operation
When towing a trailer, do not allow engine speed to drop
too low on inclines. Select a lower range (“3”, “2” or “1”)
in time, depending on the degree of the incline. This is
also valid with cruise control activated.
At extreme inclines switch to LOW RANGE mode, see
page 209.
Note:
For detailed information see trailer towing on page 190.

259
Towing
Te ch n ica l
data
Instruments
and controls Operation Driving
Instrument
cluster display Practical hints
Car care Index
Transmission selector lever, manually unlocking
In the case of power failure the transmission selector
lever can be manually unlocked, e.g. to tow the vehicle.
To do so, insert a pin (1), e.g. ball point pen, into the
covered opening below the position “D” of the shift
pattern. While pushing the pin down, move selector
lever from position “P”.
After removal of the pin from the opening, the cover will
not close fully. Only after moving the selector lever to
positions “D+” and “D–” does the cover return to its
closed position. Stranded vehicle
Freeing a stranded vehicle, on which the wheels are dug
into sand or mud, should be done with the greatest of
care, especially if the vehicle is heavily loaded.
Avoid pulling the vehicle jerkily or diagonally, since it
could result in damage to the chassis alignment.
Never try to free a vehicle that is still coupled to a
trailer.
If possible, a vehicle equipped with trailer hitch receiver
should be pulled backward in its own previously made
tracks.

310
Index
Te ch n ica l
data
Instruments
and controls Operation Driving
Instrument
cluster display Practical hints Car care
Index
Tires Driving instructions ................................................. 177
Rims and tires ...........................................................288
Rotating wheels ......................................................... 241
Tire inflation pressure .............................................250
Tire replacement .......................................................240
Winter driving instructions .................................... 180
Tow-away alarm ................................................................ 36 Switching off ................................................................ 36
Towing the vehicle .........................................................255
Stranded vehicle .......................................................259
Transmission selector lever, manually unlocking 259
Trailer operation ............................................................ 198
Trailer towing ................................................................. 190
Transmission .................................................................. 165
Transmission control - LOW RANGE mode ...............209
Transmission fluid level ...............................................234
Transmission selector lever, manually unlocking ....259
Traveling abroad ............................................................ 182
Trip computer ................................................................... 83
Trip odometer ................................................................... 80
Trunk ................................................................................. 34
Opening ........................................................................ 28
Trunk lamp ...................................................................... 111 Turn signal failure ........................................................... 91
Turn signal lamp, side .................................................. 266
Turn signals ......................................................................90
UUnlocking the vehicle ...................................................... 27VVanity mirrors ................................................................ 113
Vehicle jack .................................................................... 237
Vehicle keys ......................................................................24
Ve h i c l e t o o l s
Screwdriver ............................................................... 237WWarranty coverage ........................................................ 284
Washing the vehicle ..................................................... 280
What you should know at the gas station .................. 212
Wheel bolt wrench ........................................................ 237
Wheels ............................................................................ 240 Changing wheels ...................................................... 245