Dead furnace

We got to the Smoky Mountains campground at 8pm the other night (just at the end of generator hours).  Got set up and turned on the heat.  Nothing.

The water heater, stove, fridge, all work fine on LP.  Nothing at all from the furnace.  No fan, no clicks, nada.

It worked fine last time I tried it a few weeks ago.  Since then, I took the dual tanks off, filled them and put them back.  (I'm thinking something like vapor-lock? But as I said, all the other LP appliances work fine.)

The fuse is okay.  I don't know what else to check.  I did check all the frame-grounds I could find and they appear fine.  I haven't pulled the furnace, so I don't know if there might be a loose wire from travel vibrations.  Of course I took the cover off the thermostat but saw nothing obvious.  Is there a way to jump the furnace at the thermostat, or some other way to isolate the problem to the furnace or the thermostat (assuming the problem is in one or the other.)

No hookups at the campground, but with the generator in the morning still nothing -- but I could turn on the air con fan by flipping the fan switch to on.  It was too cold for the thermostat to allow the air con to come on.  I should have tried it after we got the inside warmed up but didn't think to.

Fortunately, we were the only people in the campground the net two nights, and the park rangers are essentially non-existent in the campgrounds in winter, so we ran the generator pretty much nonstop and stayed plenty warm with a little 1500 watt heater.
TT

Ditto, especially since the other propane stuff works.  I believe if you pull the thermostat you can jump the wires running to the furnace to test it.

Thanks for the thoughts...  I haven't really fooled with it anymore yet, but I have googled around a bit about the Dometic thermostat.  It seems they don't have a stellar reputation.  But they aren't very expensive so I guess I'll get another one and give it a try.  I'd like to figure out how to bypass the thermostat though to start the furnace just to ensure the problem isn't on that end.  Maybe it will become apparent how to do that as I dig in.

TT

Originally posted by Outbound just short the Rh and W wires - the furnace fan should come on right away.

  What is an Rh wire?  I see 6 wires, left to right, red, yellow, white, blue, brown, green.  Labeled, in the same order, +7.5, Cool, Fur, Hi Fan, Fan, Gnd.  W, I suppose is White, Rh might be Red (but that seems odd).  I don't know what +7.5 (the red wire) means either.

TT