Well Monday night the furnace went out and yesterday express came out. After some research he found 4 diodes burnt on the board. I always wonder if things are broken during troubleshooting, but as always will never know. We at least know the ABC board, basically the mother board, needs to be replaced. First bill $510, this does include a annual contract for $180. It was $125 to come out, $80 diagnostic fee and $125 for an hour of work. Not sure why the diagnostic fee isn’t part of the hourly fee, as that bumps it up to $205 an hour which is rather steep!