I just finished installing a b&w turnover hitch and a prodigy brake controller. Now i need to install a 6 pin socket for the pigtail on my gooseneck trailers. I bought a connector that plugs into the 4 pin socket under the truck, no prob. Now there are two more wires to connect on that goes to the brake controller and a hot wire. My question is where can I splice into the 7 pin flat connector at the rear of the truck, mainly which color wires are which. Any help appreciated.