PARKTRONIC, Active Parking Assist, Blind
Spot Assist or Lane Keeping Assist also
depends on this.
X
Remove the objects that are preventing the
trailer from rolling, e.g. wheel chocks.
X
Release the trailer parking brake.
Decoupling a trailer
G
WARNING
If you uncouple a trailer with an engaged over-
run brake, you could trap your hand between
the vehicle and the trailer drawbar. This poses
a risk of injury.
Do not uncouple a trailer with an engaged
overrun brake.
!
Do not disconnect a trailer with an engaged
overrun brake. Otherwise, your vehicle could
be damaged by the rebounding of the overrun
brake.
X
On vehicles with an automatic transmission,
ensure that the transmission is in position
P.
X
Apply the vehicle's parking brake.
X
Close all the doors.
X
Apply the trailer parking brake.
X
In addition, secure the trailer against rolling
away with a wheel chock or similar object.
X
Remove the trailer cable and unhook the
breakaway cable.
X
Decouple the trailer.
Trailer power supply
!
You can connect accessories to the perma-
nent power supply up to a maximum of 240 W.
You cannot charge a trailer battery using the
power supply.
When it leaves the factory, your vehicle's trailer
socket is equipped with a permanent power
supply and a power supply that is switched on
via the ignition lock.
The permanent power supply is supplied via
trailer socket pin nine.
The power supply which is activated when the
key is in position
2 in the ignition is supplied via
trailer socket pin ten.
The trailer's permanent power supply is
switched off when the vehicle's on-board volt-
age is low and at the latest after six hours.
You can find more information about installing
the trailer electrics at a qualified specialist work-
shop.
Bulb failure indicator for LED lights
If the trailer is equipped with LED lights, the dis-
play may show a malfunction message for the
trailer lights.
The trailer lighting is identified as being faulty
even though it is in working order. The reason for
the malfunction message may be that the cur-
rent has fallen below the minimum of 50 mA.
To ensure reliable operation of the bulb failure
indicator, each LED chain in the trailer lighting
must be guaranteed a minimum current of
50 mA.
Trailers with a 7-pin connector
General notes
If your trailer is equipped with a 7-pin connector,
you need to use an adapter plug or an adapter
cable to make the connection. An adapter plug
or adapter cable for the 13-pin vehicle socket
can be obtained at a qualified specialist work-
shop.
Fitting the adapter
!
Make sure that there is sufficient cable play
so that the cable cannot become detached
when cornering.
218
Towing a trailer
Driving and parking