Thank you for all the info and suggestions.
We have been gone for a mini holiday and are just back, and it is nice to see your replies.

An update:
To answer the Q about the button lay out. They are horizontal.

Also, I had purchased a new (it may be a rebuild?) head control unit, a "Programa", and when I hooked it up it did not operate any differently. Same dead center vents.

The dash is already off, so I don't have a problem delving very deeply into this to make it work as it should.

Two questions pop to mind:
Is there a good wiring diagram I can access on line for a this car that will help me track down a poorly conducting or severed wire to this sysyem. and;
Is it possible there is another computer somewhere I don't seem to be seeing in the circuitry?

Thanks in advance for your input.
This is such a nice car, I really want to make this car work as it came from the factory. (Except for the VEG thing, of course!)
Kerry