RV Repair: furnace/air conditioner problem, happy camping, 5th wheel

Question
When I turn on the furnace or air conditioner in my 5th wheel, they both come on. I have replaced the thermostat but it didn't do any good. In order to use one of them, I have to pull the fuse (or circuit breaker) on the other one. The 5th wheel is a 2003 Sprinter made by Keystone.

Answer
Rodney,
      It sounds like the t-stat is wired wrong or there may be a short in the t-stat wires.  What brand t-stat is it?  If you can find the part # I can probably help you out with what wire goes where if you don't have a wiring diagram.  Good luck and happy camping.

Darren