Welcome to the forum.
Some older coach's had fuse links off the house batteries here is a
Owners Guide lets see if yours had them. Here is a
Brochure also.
Did not see the fuse link picture but you do have some good wiring diagrams for coach.
This link will bring you to TSB's for your coach which you may have many.
All the links below in my signature have info for your coach also.
You may want to check the battery ground cables to your chassis frame.
Let us know how you are making out with this added info.