My furnace worked fine last Thanksgiving. Made a little trip this week and it got down into the 30's. Turned on the furnace and here is what happened: Blower turned on, I heard the burner ignite, ...
One of the common things that I have found is the connection to the ignitor is corroded. It is good enough for it to ignite the gas but, not good enough to get the burn signal to the board. Try removing the connector from the ignitor and then reinstall it and wiggle it around a bit. If that doesn't fix it, pull the board and have it checked at an RV repair facility. Good Luck