[nwhouston]

I had a similar problem with the factory installed "elec jack" wire when I came to where you are now. Traced it back to the outside fridge compartment, where all TM wires seem to gather, and could find no open circuit. Called The Car Show where we got the trailer, and the end of the story, we had to run new wire all the way back to the battery. Good news is we have solid power every time, and the job is not that bad. (Summary of the trace down process was to fuse every open circuit in the panel to see if that was the issue; no joy). Don't let the idea of just running two new wires to the back be daunting. Just use good clips to hold the wire to the underside of the trailer. Drill small pilot holes into the side flange of the grey water tank so you can put three clips along there as well. Ensures good ground and good power. Good luck.