BMW E61 tailgate wiring harness breaks

Common symptoms are the high-mounted brake light going out, the rear window not opening, the rear window heater not working, radio crackle and failure of the remote or central locking. The wires typically break at the hinges as the tailgate opens and closes.

The plastic cover between the tailgate and the glass is removed, giving access to the wire bundles. Soldered splices break from vibration, so a more durable method is PUR-insulated wire, a wire end ferrule and thin heat-shrink tubing. Wire sizes 22, 18 and 14 AWG are needed. The brown wire is the heater's ground wire.

It is worth repairing all the wires in the bundle at once, because otherwise the tailgate's other electrical functions begin to fail later. The job is extensive: repairing four harnesses takes a professional about 6–10 hours. When connecting, it is important to keep the wires in their correct places, otherwise the tailgate will not open.