re: beeping sound

Even When I'm driving, I'm still hearing the beeping, kind of like when the car is telling you to fasten your seat belts, but even after the light goes off, and my seat belt is on, the beeping still continues.
I was just wondering if someone has ever had this problem.
Thanks for any help,

Never mind. My back door has worked it's way open, so all that I had to do was to open and close it again. It sounded like a door was open, but I haven't used that back door for a couple of months. It's been really cold, and I thought that it was just being hard on my electronics.