If you leave the truck running when you disconnect the lights/brake power cord. Trailer disconnected comes on the screen, hit OK and then it is out of trailer mode and shut the engine off. Next time you start will be normal mode.Go into the trailer menu. Its a little clunky. You can edit it.
My 19 is annoying because I have to go in and select No Trailer after I’m done towing or it reverts to trailer on the dash every time I go somewhere. Ford might have finally fixed that bug?
The tow mode most definitely engine brakes and its a huge difference when towing. Trust me 780 miles dragging a 8700 lb boat from Seattle to CA you learn real quick how important that tow mode is. And yes the 3.5 can sound quite convincing coming off a long grade highway exit down shifting. I got more than a few confused looks from truck guys when they looked over expecting to see some kind of big truck and see a dad soccer wagon dragging a big boat