I have an 02 Cavalier, same model though. My rear driver's side window does something similar, except that when it wont go up, if you hold the button down for alittle bit, you can actually physically pull the window up. It's the only way I've been able to get the window up. It goes down just fine, but wont go up unless you pull/push it up.
Thnx in advanced for the help
