Mercedes-Benz 2013 M Class - Manual (Page 262)

Storing the ball coupling
G WARNING
Do not carry the ball coupling in the vehicle
interior if it is not secured.
Otherwise, you and others could be injured by
the ball coupling being thrown around if you:
R
brake sharply
R
change direction suddenly
R
are involved in an accident
Trailer power supply
! You can connect accessories with a
maximum power consumption of 240 W to
the permanent power supply.
You must not charge a trailer battery using
the power supply.
The trailer socket of your vehicle is equipped
at the factory with a permanent power supply.
The permanent power supply is supplied via
trailer socket pin 4.
The trailer's permanent power supply is
switched off in the event of low vehicle supply
voltage and after six hours at the latest.
A qualified specialist workshop can provide
more information about installing the trailer
electrics.
260
Towing a trailer
Driving and parking