Furnace only works when resetting fuse

I didn't get the chance to take the temperature at the vent this morning...but will do so tonight. I do know that there is more air flow at the register closest to the blower motor -- which sounds like it's under my fridge and about the center of the camper -- and not as strong at the front and rear -- which I would expect. I don't know how to jump the thermostat....but can follow directions if there is an example of how this would be done.

Thanks for any further information. I'll be hitting the manual and will do some initial troubleshooting before handing off to the dealer -- who is a 3-hour round trip. It's a new camper so it has plenty of warranty left.