as Royb mentioned, mount as high as possible to avoid head lights, and below your clearance lights to avoid glare from them. Not sure of your configuration of the rear of your unit, but when I installed mine, I removed one tail light and couple clearance lights, and this allowed me to fish the wire down the back of the unit and get to below the frame. Installed a 1/2" black corlon pipe (cheap water line) to the inside of the frame with plastic wire ties, and fished the wire through this to get to the front of the 5er. Umbilical cord is a pigtail with a male 5-pin connector (my camera only uses 2). Female connectors mounted in truck and underside of 5er by the hitch. Never had any issues. Hope this helps.
