I don't know about yours, but there are a lot of fuses on my 2010 Ford that are related to trailer lights. I'd try seeing if you can find all of the fuses that are part of it.
If you have a test plug try it, if you don't, check to see if any power is making it to connection when the lights are on.
One more thing, my TC dealer wired my previous truck wrong. I guess because the plug on the TC was wrong. In any case, there were identically wrong. That required me to rewire after getting a different truck. You don't say if this is a new to you truck or camper, or at least I didn't decipher it.
One more thought, sometimes fuses can look mostly ok, but are still bad, so if you don't have a fuse tester use a multimeter or similar to test them.
