Rear light in side panel
WARNING: This page is about a different car, the 2013 BMW X5 M, 2012 BMW X5 M, 2011 BMW X5 M, and 2010 BMW X5 M. However, it is still accessible from the selected car via links, so may be relevant.
Remove FLAP IN LUGGAGE COMPARTMENT TRIM PANEL .
Turn socket housing and pull out of rear light.