Okay, so after replacing the blower motor, the resistor and the fan switch/control cable on my Thrift Air setup, I now get three fan speeds and all the flaps are moving as they should. So why isn't there any air coming out of anywhere?
http://youtu.be/hfqt7lb0dXY
I'm thinking that maybe there is a mouse nest in there somewhere. I'm not finding any obvious blockages in the hoses going to the defroster ducts. While I'm sure this is an effective system for the time, though not quite up to modern standards, I'm sure there should be more air moving than this.