PEUGEOT Boxer Handbook page 136

Towing a trailer
Cooling: towing a trailer on a slope
increases the coolant temperature.
As the fan is electrically controlled, its
cooling capacity is not dependent on the
engine speed.
On the contrary, use a high gear to lower the
engine speed and reduce your speed.
In all cases, pay attention to the coolant
temperature.
Good practice
In certain cases of particularly arduous
use (towing the maximum load up a steep
slope in high temperatures), the engine
automatically limits its power. In this
case, the automatic cutting off of the air
conditioning allows the engine power to be
recovered.
If the coolant temperature
warning lamp comes on, stop the
vehicle and switch off the engine
as soon as possible.
See the "Levels" section of chapter 7.
Tyres: check the tyre pressures of the
towing vehicle (see the "Identification
markings" section of chapter 9) and of
the trailer, observing the recommended
pressures.
Brakes: towing increases the braking
distance. Drive at a moderate speed,
change down early and brake gradually.
Side wind: sensitivity to side wind is
increased. Drive smoothly and at a
moderate speed.
ABS: the system only controls the vehicle,
not the trailer.
Rear parking sensors: the system does not
operate while the vehicle is towing.
We recommend the use of original
PEUGEOT towbars and their harnesses,
which have been tested and approved from
the design stage of your vehicle and that
the fitting of this equipment is entrusted to a
PEUGEOT dealer.
If this equipment is not fitted by a PEUGEOT
dealer, it is imperative that it is fitted using
the electrical pre-equipment installed at the
rear of the vehicle and in accordance with
the manufacturer's instructions.