ismiv

I had a similar problem on my 2013. The first thing I did was to purchase a relay and a fuse that were missing on the fuse box located under the hood but that didn't fix the problem......short story after a lot of research and looking at wires and connections I noticed that the ground wire coming out of the harnes to the frame was rusted at the contact point. I unscrewed it and clean he area and my problem was solve. I think(not sure)that the ground wire is white and it comes directly from the harnes that attached to the 7/4 pin receiver. Follow the wire to the area above the spare tire.
Let me know if this fix your problem

David King

DIRT. Dirt was absolutely packed in the connection to the back of the module beside the hitch.

Cleaned out the crap and cleaned up the metal connectors. Works fine now.

ismiv

I'm glad you fix it

Perrett

I got my 2015 Lariat last winter and two months later, in my first tow, the Trailer Disconnected light came on and did so again and again on the 500 mile trip! But I still had breaks, lights and battery charge in the trailer, and the trailer was right there all the way!
Eventually, after several trips to the dealer, it was decided "all" that was necessary was a new computer. Since that was installed there have been no further problems. So for me it was not a circuit or fuse problem but rather a malfunctioning computer.