You might check the ground connection under the cab. The connection to the moisture sensor comes to mind, too. Corrosion on contacts can stall the CAN bus. Without CAN bus very few things function.
Sounds like the mother board in the corner post went bad. Just had a combine do the same thing. Replaced mother board and reprogramed board and all worked well again. local dealer had board on hand so it goes to show that they go often if they have a $800 board on hand.
Thanks for all the help and suggestions. The problem was two fold. First devices called wire terminators were mismatched and one was bad. The other was the circuit board in the corner post which was completely dead. I was aware of the circuit board possibility from talking to others. Turned out to be an exspensive repair.