Vacuum Lines. I had the same problem and it was due to cracked vacuum lines. Listen for some hissing under the hood and you might be able to find the source of the problem.
Mine was right around the battery.
When running I do not get any fan/air movement through the mid vents. I get defrost and I get some lower ( by the feet) air. From there I see lots of wires and some fuses (right side).
To the left of the "hump" I see a round (2" in diameter and about 1.5" thick) piece. Connecting to it is a real thin white color line.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.