Well, I Tried It
So I took the unit out of the dash last night, took it apart, and all of the solder joints were intact. I cleaned all of the contacts with contact cleaner and emery cloth and put it back together.
Once installed in the dash, the only change is now when I hit the center button, I can hear the compressor clutch engage. That's new. But still no fan or cooling. I got everything to work one time by running the AC off of the defrost button for a couple of minutes and then switching to the center button. The center dash vents did not open, but air did continue to blow out of the corner dash vents and the defrost.
Where do I go from here? Could I still have a bad ACC controller? The fact that I get no fan with the center button leads me to believe that this is an electrical problem first, and a possible vacuum problem second. Is there something with the fan motor control that differs with each "button" setting on the ACC?
Thank you for the excellent advice thus far!