Only half the vents are blowing

I am having this same issue. I think it has something to do with the bigger plastic rotator on the back right side of those pictures. It only moves in two spots.. anyone ever fix this?

 

that is exactly what mine is doing. !!!

 

Sorry in advance for replying to an old thread but I wanted to:

1) Say thanks to @2009Prius for the pictures - that got me (or my flaps rather) set straight as well. I had the same issue on a new-to-me 2006 Prius. The shaft of the servo had actually snapped off.

2) For others having this issue, I think the root cause is that the grease dries up in the flap pin tracks on the back of the disc, and the disc jams at certain points. I replaced the broken servo, greased the tracks with white lithium grease, re-assembled, and mine is working nicely again. It was a real pain to get up under there but not impossible. I did have to remove the lower trim and skid control ECU to replace the servo.