Dead Link Removed
Go to the above link for a free copy of your owners manual.
On my 96 Explorer Sport, there was a gargantuan 30A two prong fuse in the main engine compartment relay/fuse box for the trailer ruinning lights and trun signals. There were also two realys for the the trailer towing trun signal/brake lamps in a smaler realy box that is screwed into the inner fender right next to the battery in the engine compartment. I unscrewed mine from the inner fender for easier access before I popped the top off. It's just a sugestion.
There is also a 15A fuse (I think it was fuse #13) in the inside fuse box located on the drivers side of the dash panel but that fuse protects a number of other circuits as well.
Hope this is some help. The owners manual will have a bunch of good information on fuse locations and what they do. I recommend you burn a copy and keep a copy in the glove box. I have neer figured out how the owners manual ever gets separated form the vehicle but they alsays seem to once they become used cars,