2009 Charger AC/Heater control question

Interfacing an with an ipad is much more difficult than using an android tablet. Androids are open system. Some newer vehicles have the A/C controls under the CAN interface, and can be reached from OBD2 connector with special software. Much of this is proprietary, and is used for test and development. The tools and software are often dealer only, or very expensive.

The knob controls may be special and closely related to the control board. I doubt they are potentiometers, those are rarely used anymore. More likely switches, the control keeps position in memory, and responds to changes.