I discovered multiple severed wires in the tailgate/rear window wiring harnesses. Through research online I have found this is a common problem with this vehicle over several model years - search for BMW E61 tailgate wiring problems. The failures are caused by a poor design where the wires entering the hinge guides (4) for the glass and tailgate are repeatedly flexed at a sharp angle until the insulation, then the copper wire breaks. Safety issues - possible electrical short circuit leading to fires (highest load is for rear defroster); lighting failures (rear high brake light, license plate lamps and others); reduced visibility due to loss of wiper/washer/defroster; rear glass latch opening while underway, possibly resulting in loss of cargo or ingress of exhaust fumes. This is not an easily repaired problem. It would be beyond the capabilities of all but a skilled mechanic with proper tools. I discovered it when the rear wiper and rear window defroster stopped working. As I investigated I found the broken wires, along with several others with broken insulation, some with broken copper strands."

- Glenview, IL, USA