Brett, I cannot imagine the frustration you are going through! Fortunately my 08 HR Navigator is an early 08…No Konsburg. I’ve tried to warn people to reconsidering buying a rig with the chassis multiplex and a ISX engine. At least the valve issue has a $25K solution when it breaks unlike your situation.
While this may look like a nightmare, boards and relays are available plus everything is well marked… most can work on it.