2009 Saturn Aura
It seems your idle is very low and engine is fighting to stay running. Once you turn on the AC it adds more load on the engine and that's why it shuts down. With limited information give I would suggest that you start with a tune-up. Please click on "Mark helpful" if you're happy with the respond. Good luck :-)
I marked your answer helpful lol, because that's about what I would say on it.
Thanks KenF. Have a good night.
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