1983 Westy. Fridge out for combustion chamber cleaning about 4 years ago.

I have enjoyed years of great fridge use until two trips ago, about three
weeks ago, when I was driving across the Mobile Bay Causeway in the same 70
mph winds that killed eight sailors that day. It was scary enough in a
potpie camper.

Anyway, I didn't notice anything that night, but in the morning it was down
say 15 degrees from where it should have been, which as you probably know
is bad enough.  It happened again on thursday night on an overnight trip. I
shot a blast of air through it and now it won't stay lit for more than a
minute, with the "prime" knob held down or not.

So, I  figure either that it is rust, scale or debris the either got blown
in (it was raining everything you could imagine on the roadway) or
dislodged OR it is a failing shutoff thermostat that just won't hold the
gas open as it should.

Anyway to tell the difference without pulling it? I know I have to pull it,
that's no big deal, as the 10-year-old gowesty replacement fan needs
replacing to. But it would be a lot easier to accomplish if I knew whether
or not I needed that part.

Thanks,

Jim