Recently after 7 years of flawless, reliable operation my Suburban 35K BTU furnace just quit. The fuse was fine, I had plenty of LP and DC, no loose wires, even hit the on-off switch a couple of times hoping for a reset miracle... yeah right.
Having done all I could do I took it into the RV dealership and their tech quickly diagnosed the problem as a bad control board. An hour of labor - $149, and a new board - $118.99 {+ shop materials and tax} and I was out the door for less than $300.
It was nothing I could have diagnosed much less repaired. The tech said boards tend to fail after 5 -6 years so figured I got my monies worth out of the original. Good luck!
:C