has anyone done this before? under my truck on either side of the frame rail i have a black plug with a green cap the splices into my brake lights. i also have a flat plug with about 8 wires that is attached to my bumper right behind the license plate. is either of these 3 plugs used to wire the boat trailer? if so is there a harness to convert them into a simple flat 4 connector? someone said to check under my spare tire to see if i have a harness there (by the manufacturer) can anyone confirm this? thanks for any help.