Thanks Phil....not trying to put words in your mouth, just trying to come up with a solution. I've towed my Jeep Wrangler all over the US and part of Canada using this same RVi brake system with never a problem. I used the RVi twice on the Ranger and got the same brake warning. I had read...
I towed my 2019 Ranger XLT using an RVi brake system and got a brake warning when I disconnected as though the RVi did some damage. I reached out to Ford and they were of no help, suggested I contact the dealer. Are you saying that the brake warning was likely caused by the cig lighter socket...