[88 HOPN]

I have a 1997 Pontiac Grand Prix GTP that woke me up this morning. I woke up to my alarm going off every 5 minutes. It was hanking 4 times and then it would stop. Well I went out to check on my car and I find that my blower motor is running. Now heres what I did nto get. My car is turned off the keys are in my hand and the car is locked? Why did my Blower turn its self on this morning?
I don't think this will help but it's about 25-30 degrees out side.

Please Help
Baker