Trailer not charging batteries with shoreline.

To answer my own question, I talked to my AV tech back home. The converter is a part of the fuse/breaker panel just inside the front door. I pulled and visually checked all the fuses and they appear good. I have totally disconnected the two 6 vt. batteries and connected a 12 vt. deep cycle, so I'm good til I get home. (WA and OR coasts are beautiful.)