the module plugs right in no changes. than go to the harness thats right by the tailgate when opened. where the trailer wires plug in the pins need to color match side for side. simply use a depinning tool to remove the pins from the trailer side. reinsert them so that they match on both sides of the plug. you may or may not have a extra wire on the trailer side (grey and black). this was not used on my 2003 so i simply put it in an empty slot.

this will give you a 7 spade rv style trailer plug. I was unable to locate the harness separate from the module it only seems to be available as a kit. this kit also includes a 7 round to 4 flat adapter. if you just need the adapter just go to any farm store and buy one, or most hardware stores.

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2014 328xd
2015 f150 ecoboost
2002 x5 4.6is estoril blue
2003 x5 v8 sport
1996 F-250 diesel built not bought
2011 335d fbo tuned and deleted (now baby sisters racecar)
2001 x5 factory stickshift back of the barn, blown
2001 540i sport gone but still missed