NHTSA Complaint #11492046 — 2015 FORD F-150

I was towing my RV trailer behind my F150. When I backed into my campsite, I was about to pull the trailer onto wood blocks for leveling, when it felt like I had hit a curb or something solid when I tried to move ahead or back. My wife watched the wheels on the trailer and noticed they were all locked up (she took video). The suspension on the trailer flexed when I tried to gently go ahead or back. I unhooked the trailer harness from the truck and I could then move the trailer. When I got back into the truck after unhooking the harness, I noticed a strong burnt electronics smell in the cab of the truck. The odor lasted only a short time, but was very evident. The next morning upon the advice of an automotive electronics repair shop, I got a meter and checked the brake signal coming out of the back of the truck bumper connector. The brake signal was full "ON". When I pulled the trailer brake fuse in the engine compartment, this disabled the signal to the truck harness. The brake signal at the back of the truck was now OFF. I also noticed at every key ON after I unhooked the trailer harness and removed the fuse, that I go a "TRAILER BRAKE MODULE FAULT" warning on the F150 dash. It could be acknowledged and would go out for the current key ON cycle. I have to acknowledge the fault each key ON cycle now. The brake controller is the original Ford factory installed system. There are no modifications to the F150 wiring or controls. Due to a shortage of Ford dealership mechanics, I am awaiting a time for a Ford dealer to look at the problem. I am thankful that the fault occurred at 0 MPH. If those brakes on the trailer had locked up at 55 or more MPH, the results could have been disastrous for me. I have a photo of the TRAILER BRAKE MODULE FAULT warning.