Guys be aware of defective Attwood part # 33488 furnace control boards. Even brand new ones out of the box are failing at LOW (freezing) temperatures. If you heat them up with a hair dryer they begin to work again. See this thread.
https://www.facebook.com/groups/2740...7964195593987/
So if you have done everything else for troubleshooting and think it's a bad board, heat it up and try it again.