Intermittent brakes

Trailer brakes started to become intermittent on my spring sale recently. Towing with a f250 with built in controller. I replaced the male end of the 7 pin plug on the trailer and it seemed to fix it but the problem slowly came back and has gotten worse. They occasionally work after a couple seconds of applying the brakes. I also notice that my break away switch doesn't seem to work. Any ideas if these could be related? I've traced every wire I can find but have found no damage.