On a related note, surge brakes lock up when backing up unless you 1) mechanically lock them out, usually there is either a lever that you move to lock them out when backing up then snaps back when you pull forward, or theres a hole to stick a pin in, be sure to remove it or no brakes. 2. an electric solenoid hooked to the reverse light circuit (that's why a 7 wire connector has reverse as a wire), there's two types of solenoids, one is a "blocking" and the problem with that is if you have the brakes on when you shift into reverse, the brakes are locked on, so be sure to have your foot off the brakes when you shift into reverse. I'm bringing this up because if your brakes haven't been working for a while, if you get them all fixed up you might have a surprise the first time you try to back up. One more thing, in the boating world, I found the surge brake actuators only last a few years, but since you probably won't be backing your TT into water up to the axles, yours may last longer.