Mercedes-Benz Light Truck ML 320 Operator's Manual page 98

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 dealer.
Towing a Trailer
There are many different laws,
including speed limit restrictions,
having to do with trailer towing. Make
sure that your rig will be legal, not only
for where 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.
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