I had the a similar problem this spring. In my case, the Inverter wound up not charging either battery bank, so I had to replace the inverter. You may have a defective relay, blown fuse at the relay or defective batteries. Silverleaf can help you diagnose it. (541-967-8111) But, you need to charge your chassis batteries with an external charger first before calling them. Your coach will not charge dead batteries, and it needs to see a certain voltage (?) before charging begins on that bank.
2016 4519 Newmar Essex / AWD Ford Explorer