I just dealt with this today.
I replaced my headlight housings and labeled all the wires since there were spade connectors On my headlights
I labeled the wires as I took them apart, upon reassembling I transposed a couple wires.
I had them labeled and still was able to put a couple together wrong
My left headlight was a little dim, and my high beam indicator stayed on.
Well I knew something was wrong, so I pulled the headlight back out and saw that I had put the wires together incorrectly.
I imagine this caused backfeed to my headlight switch also turning on my high beam indicator light.
Anyway I fixed it, plugged them in correctly, my lights are bright, and the indicator light works correctly now.
In your case possibly two wires have rubbed together and created a backfeed as well.
I would check the headlight wiring behind the headlight
I also did the relay fix and now have bright headlights
I don't know if this will help as I believe your coach has the multiplex wiring
If you have the big owners manual it should help you find your relays, most likely in the wiring compartment.
If your coach is like mine there is a schematic drawing inside the door