[JRTJH]

Maybe they changed the process since my trucks were built ??? Who knows? All of my superduty trucks (99, 13 and 15) had the fuse/relay installed and none of my F150's (98, 05 and 10) had them installed, they were all in a package in the glove compartment...

Another possibility: The 17 and newer trucks use the SYNC system instead of the Ford My Touch system. On my truck, when I hitch a trailer and plug in the 7 Pin connector, the truck recognizes that "a trailer" (could be any trailer) is connected. There is a process in the truck computer to name specific trailers if desired. This allows tracking of specific trailers in the truck's computer system. But the truck will provide power to any trailer with a 7 pin connector that's plugged in.

On the new trucks, (as I understand it from the dealer) the truck will not recognize that a trailer is connected until the trailer is "registered in the computer", so maybe it's a "SYNC" thing rather than a "fuse" thing ????
Apparently, the truck will not provide power to the trailer battery until the brake lights have been activated by pressing the brake pedal which lights the trailer brake lights, establishing that a trailer is present and allows the truck computer to turn on power to the trailer.....

Trucks are getting more and more complex. When you have to "introduce the trailer to the truck" so they can talk to each other.... It's more complex than this old man wants my truck to be......