Mercedes-Benz GLS Operator's Manual page 230

Towing a trailer
228
Most U.S. states and all Canadian provinces
require by law:
Safety chains between the towing vehicle and
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the trailer. The chains should be cross-wound
under the trailer drawbar. They must be fas-
tened to the vehicle's trailer coupling, not to
the bumper or the axle.
Leave enough play in the chains to make tight
cornering possible.
A separate brake system for certain types of
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trailer.
Safety switch for braked trailers. Check the
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specific legal requirements applicable to your
state.
If the trailer becomes detached from the tow-
ing vehicle, the safety feature triggers the
trailer brakes.
Towing a trailer
There are numerous legal requirements con-
cerning the towing of a trailer, e.g. speed restric-
tions. Make sure that your car/trailer combina-
tion complies with the local regulations:
in your place of residence
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in the location to which you are driving
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The police and local authorities can provide reli-
able information.
Observe the following when towing a trailer:
To gain driving experience and to become
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accustomed to the new handling characteris-
tics, you should practice the following in a
traffic-free location:
cornering
-
stopping
-
backing up
-
Before driving, check:
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trailer tow hitch
-
safety switch for braked trailers
-
safety chains
-
electrical connections
-
lights
-
wheels
-
Adjust the exterior mirrors to provide an
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unobstructed view of the rear section of the
trailer.
If the trailer has electronically controlled
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brakes, pull away carefully. Brake manually
using the brake controller and check whether
the brakes function correctly.
Secure any objects on the trailer to prevent
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the cargo from slipping when the vehicle is in
motion.
When you couple up a trailer, check at regular
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intervals that the load is firmly secured. If the
trailer is equipped with trailer lights and
brakes, check the trailer to ensure that these
are working.
Bear in mind that the handling will be less
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stable when towing a trailer than when driving
without one. Avoid sudden steering move-
ments.
The vehicle/trailer combination is heavier,
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accelerates more slowly, has a decreased
gradient climbing capability and a longer
braking distance.
It is more susceptible to side winds and
requires more careful steering.
If possible, do not brake suddenly, but instead
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depress the brake pedal moderately at first so
that the trailer can activate its brakes. Then
increase the pressure on the brake pedal.
If the automatic transmission repeatedly
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shifts between gears on uphill or downhill gra-
dients, shift to a lower gear using the left-hand
steering wheel paddle shifter.
A lower gear and lower speed reduce the risk
of engine failure.
When driving downhill, shift to a lower gear to
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utilize the engine's braking effect.
Avoid continuous brake application as this
may overheat the vehicle brakes and, if instal-
led, the trailer brakes.
If the coolant temperature increases dramat-
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ically while the air-conditioning system is
switched on, switch off the air-conditioning
system.
Coolant heat can also be dissipated by open-
ing the windows and switching the ventilation
blower and the interior temperature to the
highest level.
When overtaking, pay particular attention to
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the extended length of your vehicle/trailer
combination.
Due to the length of the vehicle/trailer com-
bination, you require additional road space in
relation to the vehicle you are overtaking
before you can change back to the original
lane.