Turned it on today and the fan is vibrating like crazy again. Fiddled with it a bit again without success, so I tracked the cable into the cabinet, found a connector, and unplugged it. There are a lot of pins there, so I would think there’s a signal to the controller that the fan is on or off, but I don’t see any messages on the controller and at least I can work on this other stuff in relative quite for the time being.