Thanks to all.
Some answers in regards to what was stated/asked above. First, it is not an ATC (Auto Temp Control) model. Just the 3 dials on the head unit (Fan speed, air flow direction, hot/cold). No digital display. (see below)
There is an actuator above the gas pedal that does move (see below), but does not seem to move enough to open/close the door. I have moved the lever/door by hand, but maybe it took a little more force than the actuator has strength. Bad vacuum actuator or vacuum leak if it's not strong enough to move the door?
The other actuator I can see is lower and positioned behind the VIC (Vehicle Information Center). Haven't removed enough to see if that actuator is actually moving when I switch air flow. (see below)