I am building a raspberry pi based car computer and arduino seems like the perfect product to extend the computer's control. The system has 3 sensors (ambient temp. solar. and cabin temp) and since everything is already at 5v I believe replacing the ac controls would be well inside the capabilities of the hardware.
If that is not practical another possible direction is retaining the original board but using arduino instead of the buttons and rotary switches. https://www.dormanproducts.com/p-128361-599-215.aspx? This is the style I would like to replace or at least control with the computer and move out of sight.
I have not seen a ton of projects like that while looking the last couple days but I could easily be searching the wrongs things.