61 13 ... In-Line Plugs, 2-Pin, System MDK 3Plus 2.8
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.
Unlock lock (1) on outside at arrester hook and slide out lock (1) to side.
Unlock contact with special tool 61 1 136 and pull out cable (1) and contact towards rear.