You could have one of several things going on. Battery voltage can cause funny problems. The controller works between 9 and 15 volts. Anything outside of that, the controller goes into protective shut down. There is no rhyme or reason to what symptoms you can get. Also bad battery connections alone can cause strange things. Problems with the 8 volt sensor circuit can cause problems like this. Even if you where to get codes, you can't 100% rely on them. One sensor can cause the 8 volt system to go funny, but the controller will think it is another. I think your most likely problem is a big old rub in the harness. I would flip the cab up and look real close to the wiring coming down from the cab. The connector where the cab meets the mainframe harness likes to have rubs in its general area. I wouldn't rule out the can bus wires could be damage. With that said, start simple and check all fuses and relays first. If I was working on it after that and if the harness looked good at first blush, I'd swap controller.