I have a 2002 cavalier and it has been driving smoothly and all. Today i went to turn my heater on and my low and medium low fan levels will not blow out heat. The medium high and high levels still do blow heat. What would the problem be here and how can i fix this?

Thank you ahead of time

sounds like the blower motor took a dump. Just replace it, should be very hard or $$..

you may find some helpful hints from here
http://www.aboutautomobile.com/Diagnosis/Feel/Heater.aspx

The same thing happen to my old 91 nissan sentra gxe.
To expensive.
The car is sitting in my drive way now.... Rotting