2006 MERCEDES-BENZ ML500 towing the vehicle

251 Controls in detail
Driving systems
!
Keep in mind that in rough or uneven
terrain, adjusting the vehicle to a lower
level may cause the vehicle underbody
to come in contact with the ground and
result in damage to the vehicle under-
body. Always make sure the vehicle
has sufficient ground clearance before
adjusting it to a lower level.!Before jacking up the vehicle with
equipment that lifts one or more of the
wheels completely off of the ground,
remove the SmartKey from the starter
switch.!Please also note the information in the
section on towing (
page 472).
iThe activation thresholds are defined
by the set suspension tuning
(page 249).
iThe high-speed level is not available if
towing a trailer. For more information
on towing a trailer, see “Trailer towing”
(page 314).
iFor off-road driving, please observe the
corresponding section in this manual
(page 306).

254 Controls in detailDriving systemsWhen the highway/high-speed level is
reached, the following message appears in
the multifunction display for five seconds:
Indicator lamp2 (
page 252) goes out.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).


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 an accessory bicycle
rack.
Parktronic* system (Parking assist)
iThe vehicle is lowered to the highway
level if:

the vehicle speed is above 55 mph
(88 km/h)


the speed stays between 40 mph
(64km/h) and 55mph (88km/h)
for approximately 20 seconds
iDepending on the ADS setting
(page 249), the vehicle will be low-
ered to the high-speed level when trav-
eling at higher speeds. At speeds below
40 mph (64 km/h) at the latest, it will
be returned to the highway level.
Warning!
G
Parktronic is a supplemental system. It is
not intended to, nor does it replace, the
need for extreme care. The responsibility
during parking and other critical maneuvers
always rests with the driver.
Special attention must be paid to objects
with smooth surfaces or low silhouettes
(e.g. trailer couplings, painted posts, or road
curbs). Such objects may not be detected by
the system and can damage the vehicle.
The operational function of the Parktronic
system can be affected by dirty sensors, es-
pecially at times of snow and ice. See
“Cleaning the Parktronic system sensors”
(page 377).
Interference caused by other ultrasonic sig-
nals (e.g. working jackhammers, car wash,
or the air brakes of trucks) can cause the
system to send erratic indications, and
should be taken into consideration.


258 Controls in detailDriving systems
Parktronic* system malfunction
If only the red distance segments illumi-
nate and an acoustic warning sounds,
there is a malfunction in the Parktronic
system. The Parktronic system will auto-
matically switch off after 20 seconds.
Have the Parktronic system checked
by an authorized Mercedes-Benz Light
Truck Center as soon as possible.
If only the red distance segments illumi-
nate and no acoustic warning sounds, the
Parktronic system sensors are dirty or
there is an interference from other radio or
ultrasonic signals. The Parktronic system
will automatically switch off after
20 seconds.

Switch off the ignition (
page 34).

Clean the Parktronic system sensors
(page 377).

Switch on the ignition.
or

Check the Parktronic system operation
at another location to rule out interfer-
ence from outside radio or ultrasonic
signals.
iThe message
Parktronic on
reappears
as soon as the system senses that you
get closer to the object again, even if
you cleared the message before by
pressingèÿk or
buttonj on the multifunction
steering wheel.
iThe Parktronic system is automatically
switched on when the ignition is
switched on.
Vehicles with original equipment
Mercedes-Benz Trailer Hitch Kit:
The rear Parktronic sensor will auto-
matically disengage when towing a
trailer as soon as the electrical connec-
tion between the vehicle and the trailer
has been established.


285 Controls in detail
Useful features
When the connection is established, the
message
Call connected
appears in the
multifunction display. The Tele Aid system
will transmit data generating the vehicle
identification number, model, color and
location (subject to availability of cellular
and GPS signals).
A voice connection between the Roadside
Assistance dispatcher and the occupants
of the vehicle will be established.

Describe the nature of the need for as-
sistance.The Mercedes-Benz Roadside Assistance
dispatcher will either dispatch a qualified
Mercedes-Benz technician or arrange to
tow your vehicle to the nearest
Mercedes-Benz Light Truck Center. For
services such as labor and/or towing,
charges may apply. Refer to the Roadside
Assistance Manual for more information.
These programs are only available in the
USA:


Sign and Drive services: Services such
as jump start, a few gallons of fuel or
the replacement of a flat tire with the
vehicle spare tire are obtainable.
iWhile the call is connected you can
change to the navigation menu by
pressing NAVI button on the Modular
COMAND System unit.
iThe indicator lamp on the Roadside
Assistance button• remains illumi-
nated in red for approximately
ten seconds during the system
self-check after switching on the igni-
tion (together with the SOS button and
the Information button¡).
See system self-check (
page 282) if
the indicator lamp does not come on in
red or stays on longer than
approximately ten seconds.

314 OperationDriving instructionsTrailer towing Trailer hitches*


Only install a trailer hitch receiver ap-
proved for your vehicle.
For information on availability and in-
stallation, see 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.Electrical connections
The vehicle is prewired to accept the sev-
en-wire harness included in the
Mercedes-Benz approved trailer hitch re-
ceiver kit.
An additional four-pole conversion plug is
included in the Mercedes-Benz supplied
trailer hitch receiver kit.
For further information, see an authorized
Mercedes-Benz Light Truck Center.
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 contained in this guide can result
in vehicle damage and/or serious personal
injury. Follow the guidelines below carefully
to assure safe trailer operation.
Ask an authorized Mercedes-Benz Light
Truck Center should you require an explana-
tion of information contained in this guide.

316 OperationDriving instructionsAttaching a trailer
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 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.
The switch activates the trailer brakes
in the possible event that the trailer
might separate from the tow vehicle.

Start the engine (
page 34).

Make sure the automatic transmission
is set toP.

Set the parking brake for the vehicle
(page 52).

Vehicles with ADS*: Set the vehicle
level to Highway (
page 250).

Vehicle with ADS*: Set the ADS* to
AUTO or COMFORT (
page 249).

Stop the engine (
page 34).

Attach the trailer.
!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 func-
tion properly.iThe provided vehicle electrical wiring
harness for trailer towing has a brake
signal wire (color orange) for hook-up
to a brake controller.
You should consider using a trailer
sway control system. For further infor-
mation see an authorized
Mercedes-Benz Light Truck Center.
Warning!
G
Vehicles with ADS*:
Do not lock or unlock any doors or the tail-
gate while attaching or uncoupling the trail-
er. Do not open or close any doors or the
tailgate while attaching or uncoupling the
trailer. Make sure no one operates the ADS*
switch (
page 249) or the vehicle level
control* switch (
page 252) while a trailer
is being attached or uncoupled. The vehicle
level could change, and you could injure
yourself and/or others.

317 Operation
Driving instructions

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 under-
standing 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
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 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.
iWhen you are towing a trailer, the vehi-
cle level always remains in the Highway
setting.

342 OperationTires and wheelsStep 6 (if applicable)
If your vehicle will be towing a trailer,
load from your trailer will be trans-
ferred to your vehicle. Consult this
manual to determine how this reduces
the available cargo and luggage load
capacity of your vehicle (
page 344).
The following table shows examples on
how to calculate total and cargo load
capacities with varying seating configura-
tions and number and size of occupants.
The following examples use a load limit
of 1500 lbs. This is for illustration
purposes only. Make sure you are using
the actual load limit for your vehicle stated
on the vehicle’s placard (
page 339).