Electrical folding trailer tow hitch
The electrical folding 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 E9x since 03/2007. The electrical folding trailer tow hitch is operated using a button in the luggage compartment.
The graphic shows the E90
| Item | Explanation |
|---|---|
| 1 | Luggage compartment trim panel |
| 2 | Indicator lamp (LED red and green) |
| 3 | Button for the trailer coupling release |
There is a two-color LED for the indicator lamp in the button. The following signalling is possible:
- The LED lights up green: The trailer tow hitch is in the locked end position.
- The LED flashes slowly red (2 Hz): The trailer tow hitch is not in the locked end position.
- The LED flashes quickly red
(4 Hz):
- The drive has been activated for longer than 4 seconds.
- The current for the drive necessary for release has not been reached (12 Amperes).
The drive for the trailer tow hitch release is attached to the release unit. The ball head can only be released if the following conditions have been met:
- Terminal 15 OFF
- Tailgate open
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
- Micro-switch of trailer tow hitch release, output 1: low signal
- Micro-switch of trailer tow hitch release, output 2: high signal
After a successful check of the signal states, the direct current motor for the trailer tow hitch release is activated.
The graphic shows the E90
| Item | Explanation |
|---|---|
| 1 | Ball head articulated outwards |
| 2 | Unlocked intermediate setting |
| 3 | Ball head articulated inwards |
| 4 | Drive for the trailer coupling release |
The drive for the trailer tow hitch release consists of a direct current motor and a reduction gear. The following components are integrated in the release unit:
- Micro-switch with slide and compression spring
- Drive disc for the microswitch
- Drive disc for the release lever
- Release lever
The graphic shows the E90
| Item | Explanation |
|---|---|
| 1 | Compression spring |
| 2 | Microswitch |
| 3 | Drive disc for the slide |
| 4 | Drive shaft |
| 5 | Release lever |
| 6 | Drive disc for the release lever |
| 7 | Slide |
| 8 | Reduction gearset |
| 9 | Direct current motor |