I have the aux gas furnace under my 81 air cooled.

Last night I was driving and thought I might like to be warmer than I was,
so I turned the knob and the furnace did not come on. I felt a click on
the dial, but nothing happened as I turned it up. I hopped out and checked
all the fuses and the circuit breaker and everything seemed to be okay.
The slider was on heat, and it has always worked up to now.

As I drove away, I thought I would try the timer and see if that would
work, and son of a gun, the furnace came on and ran for the ten minutes or
so, and then shut off. I tried to just turn it back on, but no dice. The
only way it will come on is with the timer. Works with the engine running,
or not, just not with the dial as I am driving.

I will dive under tomorrow, but I really don't know what I am looking for.
Bentley has nice dwgs, but I haven't found anything that I might check.

Just thought I would throw out the question in hopes that someone can
offer any advice, or a SWAG before I climb underneath the dash tomorrow.

Thanks for the space,

John