Can't select vent, defrost, etc...help

[MalingatorGTS]

Well my fan is working and I can hear the air speed change when I use this control knob. However, when I try the selector knob, vent, defrost, etc nothing happens. It does come on when you switch it on to start air moving but it's not coming out anywhere. It sounds like the air is
trapped behind the dash.

Can someone point me in a direction please. The car is down for the rest of the week waiting on a part so it's a good time to figure this out.

I'm guessing it may be the re-circ door/flap is broken or stuck but I don't know where to find it on this car.
Thanks in advance!!