My trailer lights were working on all of my trailers last week, everything but the running lights... those would never work on any of my trailers.. any ideas? I heard there was a fuse.

My problem now is that a few days ago I had my truck backed into the lake up to the top of my rear bumper for 10 minutes. And when I pulled back out none of my lights were working at all... i checked all of the wires and they're fine.. would it have blown the fuse because it was under water or would my harness on the back have gotten water in it and made it go bad. Any help would be appreciated. Thanks