Faults with regard to backlighting
WARNING: This page is about a different car, the 2013 BMW X5, 2012 BMW X5, and 2011 BMW X5. However, it is still accessible from the selected car via links, so may be relevant.
The backlighting of the FD is influenced via the bus from the head unit. If the rear monitor does not switch on its backlighting at terminal 15, a check must be run as to whether the head unit and K-CAN are operating without faults.