There is always a PO

[twouvakind]

I need a bit info on my 72 C10 Cheyenne. It has factory AC installed. It is a bit of a hack job, thanks previous owner. What was the purpose of the vacuum switch on the temp lever....to control a vacuum operated heater valve? The vac switch is not hooked up and I have a mechanical cable to a mechanical heater valve.
The heater/defrost damper....is this mechanically operated? I have a cable to it as well. There is alot of slop in the damper lever(travel with no movement of the door)so much that the cable does not work as intended. Is there a way to reuce the slop on the damper lever to the damper door?
Any info/pics would be much appreciated.

No need to reply, truck not a factory AC cab...boy that is a huge downer.