Classic Retrofit Plumbing/Control Confusion

[Showdown]

Hey folks, I''m in the middle of my CR AC install and I have some confusion that I'm hoping the braintrust can assist with.

I have a factory AC car with the single slider.

I have plumbed everything up but I'm struggling to understand how the controls work. My car can't be powered up right now so I can't test anything out.

I intend on decoupling the blower speed control from the top slider and jumping in a rotary switch to select the three fan speeds. But before I do that I need to have a better understanding of how the system works.

This is what I *think* it does but I can't figure out how the bottom HVAC slider works.

Red lines are heat, yellow is neutral/cabin air and purple is for AC or heat out of the blower.

Please correct me if I'm wrong.

[Nditiz1]

This is correct as you have it. The bottom will still direct the flow either to the floor or the defrost BUT the air needs to work harder as instead of the air popping and going right to the redirect from the rear it now can go up and around and become stuck inside the fresh air box.

I have back dated heat in my 77. The heat redirection was a lot better before as the heat would go directly to the side dash vents off of the duct valves.

I am in the process of converting my HVAC controls to a dual upper, similar to what you will be doing with grounding the fan. This will not only improve the blast of AC to the face it should also help in the winter by having the fan force the heat to the center dash vent without forcing it to the upper/lower vents.