Vern:
I am a little surprised you can’t find the schematic you are looking for. What year is your coach?
For my 2021 Axis 24.1, after registering with Thor, I downloaded a file- Schematic details for Floorplan 24.1. The first few are floorplan details but about a dozen down is a 12V Power Distribution, Dual Battery schematic. It clearly shows the BIM but it shows the chassis and coach batteries wired incorrectly. No wonder the factory wires them backwards! It only shows the heavy battery connections, not the smaller ign, etc connections.
AFAIK Thor has no schematic that shows these.
David