Every odd day I redesign my car's "automatic" aircon logic (i.e feedback loop on a cabin temp sensor, and a user set reference temperature) to behave in some sm

Every odd day I redesign my car's "automatic" aircon logic (i.e feedback loop on a cabin temp sensor, and a user set reference temperature) to behave in some smarter manner, based on the following premises: - if it's 35°C outside, I sure as hell don't want a/c to loop on 20°C - if it's -15°C outside, I sure as hell don't want a/c to loop on 20°C So basically what I want is: - 16°C minimum (below produces too much condensation on the windshield, and is not comfortable on long-ish commutes ) - from 16°C at -10°C to 20°C at 20°C, maybe linear, maybe log, I don't know. - and cap at 20°C max inside... - ...but have a maximum negative delta of -5°C with the outside temperature (i.e 29°C outside means 24°C inside) - yet with a true absolute maximum of 28°C inside It's really not that hard and I could probably come up with a hack (has anyone plugged an Arduino into a CAN bus?) reading the inside and outside sensors, and controlling the temperature knob while reading its current setting from what the display shows, but damn, where is my car's SDK! Oh, the first world problems I have.