We had an issue with a loose neutral on our transfer switch with similar results.
Essentially we had 220 volts running through the entire rig and the only thing that saved our stuff was the inverter / converter which all the 110 plugs ran through didn't allow the current to pass it and the EMS board wouldn't allow the power for the big draw items to get juice either. Leaving the coach plugged in but not getting power.
In your case if one leg was bad you might have power on that half of the coach but not the other half.
Throw a dog bone 30 amp adapter on your connection and plug into the 30 amp plug. If your coach works then its likely the pedestal or your transfer switch.
2019 Grand Design Momentum 395
2018 Ram 3500 DRW 4.10
2014.5 DRV Atlanta (sold)
2008 Newmar 4330 (Modified) Sold