One cold Michigan morning (about -1 outside) i start my car before i head to work and a loud shrieking sound fills my car and i have no idea what it was so i turn my fans down from the heaters. The sound it still there and it sounds like a loose belt.
I was wondering if any one else has had this problem, the sound is only noticeable on fan speed 1, 2 and sometimes 3.

I will try to get a sound clip or a video, All i know is that it is annoying...

sometimes belts can freeze and squeak for a minute when its real cold out, but i don't know what that would have to do with fan speed... :?

The bearings in the blower motor are going bad I'll bet.