DC Power Issue

I sent you a PM,

Ultimately you might want to break this down into two separate trouble shooting issues. Start by focusing on the original equipment in the RV:

1. Cover solar and disconnect solar charge controller wiring. Make it as if there was never any solar.
2. Disconnect all negative terminals of the batteries.
3. Unplug shore power.
4. Take a picture of all the fuses in the fuse panel.
5. Pull all the fuses out and figure out how to open up the fuse panel.
6. Once open replace all the fuses and find where the wires come from the batteries to the panel.
7. Hook up the batteries and take voltage readings at (battery, circuit breaker posts, any fuse you can find in the line,the connections and reverse polarity fuses at the use panel.

I'm assuming all is working at this point. If so leave the system unplugged.

1. Turn on the lights until the system goes dark.
2. Measure voltage at the fuse panel.
3. Measure voltage at the circuit breaker.
4. Measure voltage at the battery.

Somewhere in the path between the batteries and the board in the power center you will find the power suddenly stops.