Fully automatic trailer tow hitch E6x

The fully automatic trailer tow hitch is an element of the optional extra 'trailer tow hitch with articulated ball head'. This optional extra has been offered for the E6x since 03/2007. The fully automatic trailer tow hitch is operated using a button in the luggage compartment.

There is a two-color LED for the indicator lamp in the button. The following signalling is possible:

• The LED lights up green: 

  Ball head locked in one of the 2 end positions and conditions required for switch-on met

• The LED flashes slowly green  (2 Hz):

  The ball head is in the locked end position ("pivoted out") and the trailer connector or an adapter is in the trailer socket.

• The LED lights up red  :

  There is undervoltage or overvoltage at the control unit for the fully automatic trailer tow hitch

• The LED flashes slowly red  (2 Hz):

  Ball head in motion or not in a locked end position

• The LED flashes quickly red  (4 Hz):
  • Control unit for the fully automatic trailer hitch is not initialized
  • Maximum current for activation has been exceeded. (obstacle or stiff movement in the mechanism)
  • Control unit for the fully automatic trailer tow hitch is faulty
• The light-emitting diode is OFF  :
  • Conditions required for switch-on not met
  • System not operational, e.g. due to blown fuse or broken lead

The trailer tow hitch can be operated as of terminal 30 switched ON. The following signal states must be present:

• Terminal 30 switched: high signal
• Button for trailer coupling release: low signal
• Terminal 15: low signal
• Rear lid contact switch: low signal

After a successful check of the signal states, the direct current motor for the pivoting movement of the trailer tow hitch is activated.

Automatic pivoting out or in (single brief press of button) 

Briefly pressing the button (for less than 1 second) pivots the ball head fully automatically from one end position to the other. Fully automatic pivoting out or in can be halted at any time by briefly pressing the button a further time.

The operating function of the button is as follows (starting position: ball head pivoted in):

• Short press on button: 

  The ball head pivots out.

• Next press of button: 

  Pivoting of the ball head is halted immediately.

• Next press of button: 

  The ball head pivots in.

• Next press of button: 

  Pivoting of the ball head is halted immediately.

• Next press of button: 

  The ball head pivots out.

• etc. 

Fully automatic swivelling out or in can only be started if the ball head is in one of the two end positions or fully automatic swivelling out or in has been halted by pressing the button.

Reversing the pivoting movement 

If the permissible power consumption of the direct current motor is exceeded during fully automatic pivoting out or in (e.g. as a result of an obstruction, stiff movement at low ambient temperatures), the control unit for the fully automatic trailer tow hitch triggers reversing. The ball head's swivel motion is halted. The ball head is pivoted back a short way in the opposite direction (reversed). It can now only be moved by continuous operation of the button (manual operation). Reversing is suppressed close to either end position and a higher current consumption is permitted. This allows the ball head to be pivoted out of each end position with more force (e.g. to release the ball head if stuck).

Pivoting out or in by continuous operation of button 

This mode is initiated by operating the button for the fully automatic trailer hitch for longer than 1 second. The ball head only pivots for as long as the button is pressed. If the button is held pressed, the ball head is pivoted in the opposite of its previous direction of pivoting. The ball head's pivoting movement stops when the button is released. A further swivel motion can only be performed in this mode. Increased current consumption by the DC motor is permissible in the continuous button-operated mode. If the current consumption permissible in this mode is exceeded, the ball head's pivoting movement stops. The ball head does not pivot in the opposite direction to its previous direction of pivoting (no reversing in this mode). Only if an end position is reached in this mode is automatic pivoting out or in possible again.