this morning i was driving home from class w/ my heater on...then suddenly the A/C turned on automatically...why may cause this? should i be worried?

 

Did you have the defrost on?

 

if you mean it just starts blowing out cold air while you have the heater on, then ur thermostat is shot... replace it, it's fairly cheap and crazy easy to replace. Just make sure you put it in EXACTLY the way you pull it out and refill whatever coolant you lost