OldAir Heating and AC Questions

[Magnuman]

I bought a project of a 1971 Blazer that I am trying to complete.
The previous owner had purchased and partially installed an OldAir Heating/AC system for the truck. The Blazer originally was equipped with an AC system.

My questions are:
There seems to be no cable connection for the middle lever on the stock controls for the OldAir system.

When I called OldAir they said this cable and lever does not get used.
I am just wanting to confirm this.

I also inquired about the passenger kick panel vent assemble and the cowl vent assembly. On the original ac sytem these opened and closed with actuators. Old Air told me that these are no longer required and should be in the closed position when the system is operating, due to recirculation of cabin air for their system.
Again, I am just wanting to confirm this as their installation specs didn't have anything on this. They did not say to abandon, disconnect or integrate.

Any insight into the Old Air system for 67-72 would be appreciated.

Thanks.

[john]

I believe there is a micro switch that attaches to the control,I just cant remember which lever. Do you have the installation instructions? On my non A/C control it goes on the cold-hot lever.