61 31 246 Removing and installing/replacing rear lid button
WARNING: This page does not describe the selected car, but rather 18 other vehicles, including the 2015 BMW Alpina B7L xDrive, 2015 BMW Alpina B7 xDrive, 2015 BMW 750i xDrive, 2015 BMW 750Li xDrive, and 2015 BMW 740Li xDrive. However, it is still accessible from the selected car via links, so may be relevant.
Operation is described in:
Removing and installing MIDDLE TRIM STRIP ON REAR LID .