It could be your seat circuit which is cutting your header out. We had a randomly dropping out header no longer running. There is a timer circuit board in your RH panel. The idea being if you leave your seat for more than about 5 or 10 seconds your header will stop running. I bypassed it on our combine so I can leave the seat if and when I want as it was failing. Short circuiting your seat circuitry won't help as it was an issue with this circuit board located in the side panel. I bypassed it and never had a problem since. Are you at F.V. SK? (name sounds familiar!) I might have bought lentils from you!
I'm having somewhat the same issue but on ours just the pickup stops. Feeder house keeps running. Been combining for days with the hydraulic bypass open so pickup belts run none stop. At least we can keep running.