Thanks.
Seems likely, but awkward location for testing or service. My aux start switch does work but it seems coil is weak. It cuts out after 30 sec or so.
Let switch return to off and it works again, cuts out again.

After thought: Is there a "salesman" battery disconnect switch on Barths? .. 87 Regal 454.

quote:

Originally posted by MJ56:
I can't identify it in any wiring diagram I've seen.

You are now into the mystery world of Barth wiring. One of the many ways that Barth can differ. Some Barths were built with all wires red! I am most familiar with the GM chassis.

You can find most of the chassis on the GM wiring diagram here on the site. Lights, fuse panel, engine, fuel system are there.
If you received any wiring info with the coach, be grateful. I got none with mine.
Some of the appliances have wiring info. Other than that there seems to be little documentation.

We see a lot of variation in the early GM coach wiring. Battery locations vary, panel locations vary, generators, lights, levelers, etc. Worse yet we see some DIY wiring from owners which is marginal in size and quality.

Good luck with your quest.

I did get some additional wiring info in my binder.
I am grateful, you reminded me to look again for the aux boost wiring. Didn't find that but found a diagram for aisle lights switching.
It is on 3-way switches, one in the dash (rocker, labeled) and one in a 120v style wall switch in bdrm. (verified on blueprint)
There is no way to tell which position of switch is on because recent tests did not light from either switch. Could be all 4 bulbs or fuse are out. Could be they are not easily seen in daylight.
My point is, the diagram indicates it is on chassis system.
It is possible a light is left on.

My question is, could there be draw from corrosion or leak to ground or short or something in all that wiring from front to back of 2 switches and 4 sockets and grounds, being energized but no apparent filaments to close circuit?

I will continue testing but I want to explore these phantom theories here. I know that there is a potential for draw, anywhere along a circuit that it can find a return through the path of least resistance. I have seen an exterior marker light with lens that was so full of water, debris and corrosion, with a broken bulb, that it could easily have turned into a conductor.
I know theories won't solve the problem but I have to wonder and I hope this discussion is helpful to others.