Hi, and welcome to the forum. I'm not familiar with your vehicle so can't offer any specific help but you can download the owner's manual in PDF format from this
Ford site. I had a quick glance at it and I see there is a fuse specifically for the 'Trailer Tow Electric Brake' - that's listed as fuse 108 (30A, located in the Power Distribution Box).
There may be other fuses and relays of relevance, but hopefully somebody else will come along who is familiar with the trailer wiring.