My frigidaire fgid2466qf1A dishwasher is throwing the UO (vent fan open) error.

I removed the unit and inspected and the vent fan is coming on whenever it is connected. When the fan is on the flap comes open which seems to be the way it should work. When I disconnect the vent fan assembly from the wiring harness the fan goes off, and the flap closes as it should. I also tried removing power to the dishwasher and as soon as I enabled power again to the unit, the fan came on again.

I understand the standard methodology for UO to be that "the vent fan assembly should be replaced, and possibly the control board". I believe the vent fan assembly is MFG # 154861101 and the control board is MFG # 5304504782. Vent fan is over $100, and the control board is around $85. Other complaints I have seen for UO seem to indicate that the fan is getting clogged up or the arm is sticking. My unit doesn't have those issues. Which would you replace first in this situation vent fan or control board?

Thanks