If you have KeyTV, I bet the unit has an internal failure, seen quite a few. The furnace could be a few different things and the sail switch is often blamed, seldom convicted. The control board is a more common failure, but only a proper diagnosis will confirm.
There isn’t any diagnostic “test” for the KeyTV that I’m aware of. You may be forced unfortunately to get the unit to the dealer. If you don’t get Keystone to authorize a mobile tech then I would try to set an appointment as a “waiter” and possibly look for “day care” for the day for the pets, my daughter in law worked at such a place before they moved.
2012 Copper Canyon 273FWRET being towed by a 1994 Ford F350 CC,LB,Dually diesel.
Airlift 5000 bags, Prodigy brake control, 5 gauges on the pillar.Used to tow a '97 Jayco 323RKS.
Now an RVIA registered tech. Retired from Law enforcement in 2008 after 25+ yrs.