Reb- Welcome to iRV2, best place on earth for all RV Q&A.
I had a 94 F-150 w/factory tow package. It had a
6 pin tow plug. As you can see from clicking on that link, the center pin was to provide 12V thru the plug. If that's what you have, check the center pin for 12V, and if its there, your problem is in the trailer. If not, trace the center wire back to find your fuse (might be an in-line fuse near the plug).
If you have the 6-pin, first thing I'd check is whether the truck & trailer both follow the color conventions shown on the linked diagram. If the conventions are not followed, you'll need to make your own diagram of wire colors & pin position functions. If you don't have 6-pin, you'll need to start defining what you do w/more info here to get better feedback. You can start w/year of truck & camper to get readers in the ball park of what we are diagnosing.