What is this?

[79Chevypickup]

Alright here is what I did to fix it.......
After I took everyones input this is what I did...

Connected a NEW hose from the black sphear vacum thing to the post thing sticking out of the intake....

Then I found the control arms and cables ontop of the heater core distribution box and figured out that the one towards the front of the truck is for hot and cold... the one for the defroster and such is toward the seat (this I could see after removing the glovebox)
I started to play with the defroster one to make sure it worked, well it seemed to be stuck, just then at the same time my 2 and 1/2 old son sitting in the drivers seat put the truck in neutral (engine off of course) so as I try and hurry up to get off my back from the passanger side and get to the brake I BRAKE THE CONTROL ARM...... crap I am thinking, right?
NO, what ever happened made it so that the control arm is lose the flaps move freely, HOLY CRAP!!!
So being that I work for your local cable company I got a butt load of zip ties....Put it this way... I know have a defroster and vent and heater.....
Now all I need is for one of you guys that have an extra ac compressor laying around and I will have ac... Just kidding...

But there is one more thing I had to do before I achieved full defrostness..... I had to block off the bottom box... I think something acctually goes there... I can touch the metal flap on the very bottom without removing anything....
But I am good now...

Thanks to all of you!!!!
You guys are the reason that I come to this forum every single day multiple times!!!!
That and so I can try and be as cool as yall and try to help someone out....

THANK YOU !!!!!!!!!!