Welcome sledriver to the Newmar forum & irv2.
Here is a link to help explain you battery set up 12v Side of Life.
What I would do is check your ground wires off both sets of batteries, house and chassis battery to frame of coach. If they are dirty and corroded clean them up and refasten with new bolts and star washer to keep tight to frame.
Your alternator should charge your chassis battery and house batteries. Make sure all connections are clean.
Your house batteries will be charged when your shore line is plugged into 30 or 50 amp service or 110 with adapter.
In most coaches your Generator is started by your house batteries. Your Gen has a ground wire to chassis frame also.
The house batteries are charged by your converter when shore line is plugged in.
On newer motor homes a BIRD
is installed that will control charge of house batteries and when they reach full charge will switch converter charge to the chassis battery's.
Unless someone upgraded for this you wouldn't have Bird.
Picture of BIRD.
I'm sure others will have something to add, enjoy the forums and do post often.