Just bought a 2012 Tundra with the tow package. I am about to install the trailer brake jumper harness and brake controller. I can match four wires between the harness and the controller. However, the harness has an extra wire, colored green. The instructions on the trailer brake jumper harness reads, "GREEN: HEADLAMP SWITCH TO VEHICLE TRAIL LAMPS". I assume trail is tail, but what's it for and where does it go, since I have tail lights at the trailer wire sockets under the rear bumper?
I read on one of the posts that I should provide a body ground under the dash for the trailer brake circuit. I will tap into the ground wire and make a connection to the ground screw.
Also, there must be a directional/brake light module somewhere on the truck to allow trailers without separate amber directional lights to work. Just in case it fails sometime, does anyone know where it's located?