So I have a 2013 Ultra Classic CVO. To wirethe backoff xp so that the tour pac and the main brake light works, you have to deal with two different brake electrical circuits. The main rear light, and since I have added the bumper and lower fender light, can be picked up next to the battery and just coming up from the rear fender. Find that harness and you can tap into it with the red, black and in my case the red and white wire at that point. Now the center tour pac light is a little different as it runs from the main tour pac grommet (left bottom), and up a wiring sheath on the left hand frame. What I did was put a small hole in that sheath and fished a red wire into the tour pac. Since I did not want my luggage rack wing led lights to flash, I tapped into the Harley red/yellow light that runs into the tour pac center light. Not real hard, maybe one beer. Now my tour pac light flashes along with the main stop light and my fender light. If you want the tour pac wind led light to flash as well, just tap into the line as it comes out of the grommet and before it splits to the center and led light. Pretty easy. I put the actual model under the drivers backrest attachment point so nothing interferes. Clean set up. What would be really slick, if the the signal dynamics people made a plug and play harness. Seems like it would be easy to do and I would pay the extra money for it.