The AC disable is the button on the front of the controller labeled A/C. It lets the fresh air in or recirculates the air. The same as "Max A/C" settings on other autos. It open and closes the recirc door.
The diagrams i have are basically the same as haynes. The A/C one is a little different.
air-conditioning-heater-circuit-1-of-1.pdf
air-conditioning-manual-a-c-circuit-1-of-1.pdf