61 13 ... In-Line Plugs, 4-Pin, System DFK ELA
WARNING: This page is about a different car, the 2007 BMW 550i and 2006 BMW 550i. However, it is still accessible from the selected car via links, so may be relevant.
Press arrester hook in direction of arrow and remove lock (1).
Installation instructions:
If necessary, side lock must also be unlocked with screwdriver.
Unlock contact with special tool 61 1 136 and pull out cable (1) and contact towards rear.