51 16... Removing And Installing/Replacing Inner Trim On Window Frame (Roller Sun Blind) Of Left Or Right Rear Door

Unclip trim (1) and pull out in direction of arrow from door trim (2).

Fig 1: Removing Door Trim

Courtesy of BMW OF NORTH AMERICA, INC.

Installation: 

Locking rails (1) of trim (2) must not be damaged.

Fig 2: View Of Locking Rails Of Trim

Courtesy of BMW OF NORTH AMERICA, INC.