Attaching the ball neck
WARNING Danger of accident‑ and injury due to incorrectly installed and secured ball coupling
If the ball coupling has not engaged, it can become detached during driving and endanger other road users.
Engage the ball coupling as described and ensure that it is securely installed.
WARNING Danger of accident due to non-engaged ball coupling
If the ball coupling has not engaged, the trailer can become detached.
Always engage the ball coupling as described and ensure that it is securely installed.
Note the number of the key that belongs to the ball neck of the trailer hitch.
With this number, you will get a replacement key at a Mercedes-Benz service centre.
Take the ball neck of the trailer hitch out of the stowage space on the right-hand side in the rear.
Unlock lock 
in handwheel 
with the key. The red mark on ball neck 
must be aligned with the green area on handwheel (fitting position).
in handwheel with the key. The red mark on ball neck must be aligned with the green area on handwheel (fitting position). If red mark 
is not aligned with green area 
, unlock lock in handwheel with the key.
is not aligned with green area , unlock lock in handwheel with the key. Pull handwheel outwards. Turn red mark into green area until handwheel engages.
outwards. Turn red mark into green area until handwheel engages. Slide ball neck vertically into the holder until it audibly engages.
vertically into the holder until it audibly engages. The ball neck will lock automatically. The green mark on handwheel is aligned with green area on the ball neck.
Only if the green mark on the handwheel is aligned with the green area on the ball neck is the ball neck securely engaged.
Lock lock in handwheel with the key.
in handwheel with the key. Remove the key and place cap 
on lock .
on lock . The ball neck is securely installed only if the ball neck can be locked and the key removed.
Store the trailer hitch key in a safe place, e.g. in the vehicle document wallet.
If you cannot remove the key, the ball neck may be dirty.
If you still cannot lock the ball neck after cleaning it, the trailer hitch is damaged.
Remove the ball neck.
Safe trailer operation is not guaranteed. The ball neck must no longer be used for trailer operation.
Have the trailer hitch checked at a qualified specialist workshop.
Overview of lashing points
Example: variable lashing points in the guide rails
Do not attempt to modify or repair the lashing points, tie-down eyes or lashing materials. Read the information on qualified specialist workshops More.