I recently bought a 1996 Lite Craft popup truck camper and everything is in great condition! One problem though, when I'm plugged into 110AC everything works but when I'm running on the battery the furnace won't work. The blower motor is a DC motor so I know it's drawing power from the battery, even when I'm plugged into 110AC. So when I switch my converter to "battery" and turn the furnace on, the blower motor kicks on but not at full power and struggles then the furnace won't light. And yes it's a new fully charged battery so I'm lost with why the furnace won't run on the battery? I went to Camping World but they want $100 just to diagnose the problem. So if anyone here can think of what's going on or knows how to fix it....I'd buy you a steak dinner!!!