1977 Dodge Sportsman Electrical Issues

[Barimpact]

I recently bought a 1977 Dodge Sportsman RV with the 360 V8. I bought it as a non running project. The issue I can't figure out is why nothing on the van side seems to be getting power. The battery under the hood has 12.4V and when the circuit breaker is reset, lights in the back of the RV turn on (the lights above the counters), but none of the vehicle related lights turn on (headlights, hazards, parking lights, etc) and there seems to be no power through the ignition switch either. I even hooked up my battery jump starter to see if the battery had dead cells, but still no change. The fuses under the dash seem to be in tact, the battery terminal clamps are brand new (I replaced them), the ground cables off the battery have strong continuity to the chassis ground. The battery in the rear is dead as a doornail but I figured this wouldn't be related to making the vehicle run and drive. Any suggestions on next steps would be greatly appreciated, thanks.

Secondary note - I do have a repair manual for the Dodge vans this age, but there are no RV components in these repair manuals.

[Skip426]

The firewall connections for the battery power to the dash board were a big problem in Dodge vans ( P/Us) of that vintage , melting and taking out the fuse wire was a common failure.