Correct on the dip switches, they are located on the rooftop AC. I had to adjust mine because I ordered my coach with 2 15K heat pumps and my thermostat would not show HP for my zone 2. I went up and noticed the dip switch on my back AC for heat pump was not in the on position. I put it on and did a reset on the thermostat and it showed up and worked fine. I believe the dip switches are only to send a signal to the thermostat so you can control the devices. If your thermostat shows furnace than it should work and it's not your dip switches in the wrong position.
Now one issue I did have with my coach was that I was not getting propane to my stove or front furnace, but was getting it to the hot water heater and rear furnace. My issue ended up being that when my front passenger side slide would go out it would kink the propane line and I would get nothing to the furnace or stove. Bring the slide in and all would work great. I had to spot tie the lines up so they would not kink anymore and now they both work fine! Not sure of your floor plan, but I would see where that propane line runs and if it is in the slide out, see if it is getting kinked when the slide is out. Bring the slides in and check if it works. If it does, put each slide out one at a time and see if the heat goes away, if it does than you know which slide out is kinking the hose and you can trouble shoot further. Hope this helps out!!!