TowX,

Good luck with your electric trailer brake controller installation. There are two very good Word documents on this forum on how to do it with the Tekonsha Prodigy. It took me the better part of a day, but I morphed the two into what seemed like the best of both methods, ultimately using the passenger side light control module for the brake signal wire to the unit. It definitely controls the four trailer brakes well, but I've had an issue with that too. The triple speed blinker rate for the turn signals also intermittently turns the brake controller current on and off as well while slowing down (and causing the trailer to jump), essentially making it impossible for me to decelerate smoothly and reliably unless the turn signals are off. As I said, this is intermittent and independent of towing speed or magnitude of deceleration. It may happen at one stop, and not the next. It may even sometimes trigger/pulse the brake controller at steady speeds when only changing lanes. Even the trailer shop I took it to this past week couldn't find a cause of the problem, despite seeing the problem in action.

JCL,
As you recommended, I wonder if running a separate ground wire from the trailer light cable to the X5 frame might fix any or all of these issue. I may investigate that this weekend....

surgeondress