Ok, first On most coaches the status display shows not the condition of the battery but the voltage on the house power panel (12 volt panel) this.... if plugged in... Is the converter output.
Next we have the famous "Salesman" switch, properly called the Aux Battery Disconnect Switch. If this is in OFF/Disconnected/Store state (position) then the batteries are NOT connected to the house, or for that matter to the converter. And this is suspect #1
Then there is a fuse and/or Circuit breaker somewhere.. May be the right hand most fuse or fuses on your fuse panel, may be elsewhere
Finally we have the assorted connections, and the batteries themselves.