61 13 ... Circular Plugs, 7-, 8-Pin, System D2.5
Carefully pull off rubber grommet (1).
Carefully push back retaining lugs (2) of internal connector (3).
Slide internal connector (3) in direction of arrow until retaining lugs (2) lock into locking groove (4).
With special tool 61 1 132 (ejector), press back arrester hook (5) of appropriate contact and pull out cable.