Welcome bigeagle to irv2.
In the black box with the clear plastic cover on right hand side of your fire wall you have your solenoids and 12V copper buss connectors for chassis functions.
The left hand solenoid has a 5 amp fuse in a fuse holder attached to lug nut left hand side of solenoid.
If I remember correctly there is a green wire connected to the fuse holder clip.
This clip attachés to one of the spades of the fuse.
What happened to me was the clip popped off fuse spade and the engine would not start.
Its difficult to see the picture I will post will show you why.
Below this BIRD is the solenoid if you have this black box it maybe to far to the right to see the solenoid plus left lug nut also, The Newmar Mountain Aire has this problem. My coach its easy to see.
So if you are able to see lugnut you need long longnose pliers to force the clip back on the fuse spade which is not easy.
If this is your problem you may have to extend a wire off lugnut and place a new fuse holder and tie off on the wiring bunch of wires.
The clip worked loose from vibration and was a pain trying to find the problem because we thought it was a starter solenoid problem.