[Carl n Susan]

I too am wondering how you found the short?

It is true there are no wiring diagrams available from Montana. But over the years we have learned some of their tricks. You don't say what year/model Montana you have so this may differ from your configuration.

The 120V supply comes in to the slide from a junction box under the slide (at the back). This has been a frequent source of trouble as the junction box tends to leak and corrosion causes issues. I believe the power then runs over to the middle of the slide where there is a channel vertically. It powers the 120V plug and sconce light in the wall and then goes up to the ceiling fixture. Alternatively, they might have run the 120V power run the power up the wall near the entry, and then along the top of the slide with a drop down to the sconce and wall outlet. Bur that would require a junction box in the ceiling and I have never encountered one. That is why I believe it comes up from the floor feeding the various connections along the way.

A continuity test of the wiring along this path may uncover the root cause of the problem.