Please see photo's of my new 2011 X5 3.5i Premium with BMW dealer installed trailer hitch and power connector. Installation is neat and bumper trim is OK. Hitch is supplied with mating plug that has 4-wire flat harness adapter. Programming required about 3 hr. at the dealer. See detail photo of socket receptacle with wiring diagram. I have surge brakes on my single axle boat trailer. Center pin is identified for "backup lamps" and this will be connected to the trailer surge brake solenoid to release brakes when trailer is backing up.

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