OK. so I checked the fuses. One on the back of the Coleman Mach thermostat and one labeled "furnace" in the fuse box next to the breakers under the back bed. pulled, checked, cleaned. all good. I discovered that there is a switch next to the sofa against the kitchen cabinet which when turned on, I can hear the furnace light up and I can hear the burner going and warm exhaust coming from the exhaust vent outside. This turns on no matter what the thermostat is set at. But the fan never kicks on.
I am currently plugged into shore power. Furnace is Atwood 8500-IV I believe.