When mine failed it would start heating and shut down maybe 1 min. I put hand over heat vent to feel vent push air. It was cold than turn warm than cold and shut down. I doubled checked propane and tanks where full and working. It was under warranty. Dealer found same as I did and pulled furance out, the main board was shot. I do not know how they tested the main board to found the problem. They also found a black wire was cut in half due to the fan spinning with furance working. Others have had the main/mother board fail. Your saying no heat so, it could be different problem?
2013 24RKSWE (27ft TT) Cougar 1/2 ton series
2013 Ford F350 4x4 CC 6.7 engine, 8 ft bed 3.55 rear end lariat package
Retired from Oregon State Police in 2011 than worked another 9.5 years as a small town traffic cop:
As of 05-2020, I am all done with 39 years total police work. No more uniforms for me.