52 26... Emergency actuator for rear seat backrest
WARNING: This page is about a different car, the 2010 BMW 550i, 2009 BMW 550i, and 2008 BMW 550i. However, it is still accessible from the selected car via links, so may be relevant.
Open luggage compartment.
Insert screwdriver for levering in snap-in hole of rear seat lock.
Press screwdriver to center of car and in so doing press supporting point (1) of Bowden cable outwards.
Courtesy of BMW OF NORTH AMERICA, INC.