I have never had to code for my a/c. I drive my car maybe once a week now and every time I get in my car the settings are were I left them.

 

Your previous owner probably had it disabled at the dealer. Its so common of an annoyance you can turn it off just using ISTA/P

 

happens to me sometimes. turn the nob down to the lowest setting then press the ac button to disable. select the window defroster instead then turn that off but make sure its on its lowest setting and then turn the veh off. then when u start it again it should not turn on automaticly. also check to see that the heat settings are turned up under climate on idrive