'05 Outback - only dash and defroster vents work

I am experiencing a situation with an '05 Outback whereas the dash vents work fine and the defroster works. However, when I set the control to floor vents, the air continues to come out of the dash vents.

I am assuming that there is a servo in the dash that diverts the air for vent, floor or both.

Are the vents doors operated by servos or are they vacuum?

I am not familiar with Subaru's, it is my Mother's car. I work on trucks for a living. Any help or ideas would be greatly appreciated.

Mikado