Initial Inspection
Trailer Hitch Maintenance: Check Operation
NOTE:
- A trailer in which the wiring and lights are operating perfectly or the VAS 1537 A trailer test cable is required to perform this check.
- Please note that, if the VAS 1537 A trailer test cable is used, only vehicles with a 13-pin plug can be checked.
- The test cable can be attached to the trailer socket to locate faults. The plug has 13 pins; adapters are required for 7-pin sockets. Because of the build-up of heat, ensure that a thermal circuit breaker is used in the test cable.
Test cable VAS 1537 A:
Checking Operation of Trailer Hitch Socket
1. Connect the test cable to the trailer hitch socket on the vehicle and lay the cable to the front.
Procedure
NOTE: The LED for permanent positive -9- is lit for the entire duration of the test.
1. Switch on the ignition and change through the following loads in turn:
- Switch on left direction indicator -1- or right direction indicator -4-, the direction indicator and the direction indicator pilot light for the trailer in the instrument cluster light up; press the relevant key (-B- for left or -C- for right): now, LEDs -1- or -4- and the direction indicator in the instrument cluster should not light up.
2. Actuate the brake pedal - LEDs -6- should light up.
3. Switch on the parking light - LEDs -5 and 7- should light up.
4. Switch on the parking light and rear fog light. LEDs -2, 5 and 7- should light up.
- With the tester behind the vehicle, press button -A-, the rear fog light should light up on the vehicle, LED -2- should go out.
5. Switch off the light, shift into reverse gear.
- LED -8- is off, the reversing light on the vehicle should light up.
- With the tester behind the vehicle, press button, -D-. LED -8- should light up and the reversing light should go out.
General:
-10- Charge positive
-11- Ground for charge positive
-12- Trailer detection
-13- Depending on the load (heat build-up) in the tester (the more LEDs that are lit up), the tester is switched off and this is indicated by the lighting up of this LED. Disconnect the tester and let it cool for at least 20 minutes.
Checking Electrically Retractable Trailer Hitch (AHK)
WARNING: Risk of injury and damage when retracting and extending the ball hitch.
- Make sure that no persons, animals or obstacles are in the movement range of the ball hitch.
- To interrupt the swivel action of the ball hitch in the event of danger, touch the rocker switch -A- again.
- Never swivel the ball hitch when a trailer is attached or when bicycle racks, for example, are fitted to or mounted on the ball hitch.
- Only use the trailer hitch when the ball hitch is extended fully.
- Never insert tools of any kind into the ball hitch swivel mechanism. This could damage the locking mechanism and as a result, the safe operation of the trailer hitch could no longer be assured.
- Check that the ball hitch locks into position correctly before every journey.
Overload protection
NOTE:
- The swivel action of the ball hitch is interrupted in the one-touch function of the rocker switch if resistance interferes with the movement sequence. The interruption is indicated by the rapid flashing of the red LED in the rocker switch.
- Overload protection is switched off by pressing the rocker switch for at least 2 seconds.
1. Swivelling the trailer hitch out.
Requirements:
NOTE:
- The vehicle must be stationary.
- Rear lid or rear window must be open.
To swivel out:
- Touch rocker switch -A-.
- The ball hitch moves automatically into operating position.
- The red LED in the rocker switch flashes until the operating position is reached.
2. Retracting the trailer hitch
Requirements:
NOTE:
- The vehicle must be stationary.
- Rear lid or rear window must be open.
- Trailer must be unhitched.
- Connectors (and any adapters) must be removed from the socket.
- There must not be any accessories on the ball hitch (e.g. ball protection cap, bicycle rack, etc.).
To retract:
- Touch rocker switch -A-.
- The ball hitch moves automatically into operating position.
- The red LED in the rocker switch flashes until the operating position is reached.