Windshield defog airflow failure

Hi!

I have an issue with my gen3 Prius. When I set the air conditioning to windshield defog the airflow comes to my leg too. I looked inside the dashboard as I can, I find a servo which not move in any set of the A/C controll. Can you tell me what this servo for:
(This is on the right buttom side of the air control box, below the air mix control gear)

 

I'm talking about when I use the separated defogger button. In the Toyota service they are not able to tell me how much will be the repair, and how long will it take...But I guess it will probably cost more than I can easily pay...
I disassembled the dashboard as much as I could alone.
There are three servos, one is set te internal circulation/outside airflow (it works). The second is the main airflow control servo, it moves when I push the "mode" button (but I guess, in the defogger setting it stops before the right position). And there is the third servo, which was on the picture, this looks like moving some kind of a shutter in the bottom inside the airflow box, but is not moves any of the air condition setting (including the plasma cluster turned on/off)
I hope this is the reason and solution of my problem, because it is easy to replace. If the main control servo fails, it would be a hard to change, because it is behind the blower fan, and the whole aircontition box removal is needed to replace. This should be done in the Toyota service for a lot of money.
Here are more photos I shot from the leg's airflow shutter:
Legs only mode:
Upper body only mode:
Defogger only mode (NOT legs ang defogger):
I have no picture when it set on the legs and gefogger together but the shutter is ca 1 cm (half inch) upper than you can see in this picture.

 

I think it's better on a separated button. Because if you need fast defog the windshield you don't need to push many times the mode button, and activate the A/C etc etc. Most cases in winter time I use it's auto function...

 

Thanks for these memories, but we are going off topic...
The question is what those servos controll in the Prius's air condition?

 

I think I found the answer to my question. This servo probably the air mix (hot/cold air) servo.

 

Thank for this sheet. As I see, my air flow control servo has a malfunction, it stops in the wrong position in defogger mode. Oh sh*t, it will be an expensive repair...