The food in our FF was freezing because the damper door was not closing. I removed the damper control assembly from the fridge and took apart the plastic/foam housing so that I could access the actual damper door and motor. I manually pushed the door shut and plugged it back into the fridge.

I used the temperature display to enter the self-diagnostic mode and ran the Open Damper Test by entering 1 & 0 on the display. The damper door started to creep open, but at 1/4 open it hesitated and started to slowly flutter back and forth. It would not fully open or fully close.

I ordered a new damper control assembly and plugged it in. When I ran the Open Damper Test again, the new assembly had exactly the same behavior as the old one. It opens part way, flutters back and forth a few times, and then stops moving. So apparently I jumped the gun by ordering a new damper.

Any tips on what to check next? Possible motherboard issue? Thanks.