If you overheat any car it will shut it down, in most cases. By running ac you added extra load to your engine, which in turn makes it work harder...harder means hotter! Have you changed out your thermostat and bled your coolant system lately? Those are your first 2 culprits, then see if your waterpump is weeping any fluid, indicating a failing pump. Technically your car gets hotter when you turn it off, no circulation! So also check to be sure your fans are working too.Hope this helps.