Did you check all of the circuit breakers/fuses?
There is an on/off circuit breaker switch on the furnace that is accessed by taking off the outside door. If that pops, the furnace is totally dead as you describe. Mine was in the off position when the trailer came from the factory and I had to find the switch and turn it on. Indicates to me that the furnace was never tested at the factory.
John W. Irwin
2005 Classic 28 "Sabre-Dog III"
2013 Silverado 2500HD Duramax/Allison LTZ
WBCCI #9632, TAC TX-10