Maxxair Fan Dead?

[MN_Rider]

Hello GD family. Looking for some help with a Maxxair fan. We have a 2019 354M with one Maxxair in the kitchen and one in the bathroom. The kitchen unit is working fine. The bathroom unit is not working this spring but was working last fall. The fan is not responding to any of the 4 buttons on the control panel and will not start the fan or open the lid. So far I swapped the control panel from kitchen to bathroom and same result: kitchen works, bathroom does not. I also swapped the circuit boards with the same result: kitchen works, bathroom does not. I tested the power to the fan, and I have a nice 13.71 volts. When connecting the fan to power, the unit attempts to close the lid, which should be a good sign... but that's it. Still no response to control panel buttons. The results are the same whether the rain sensor is connected to the circuit board or not. What else is there to check? All suggestions are welcome.

I was not sure to post this under HVAC or Electrical section...