'88 Bonne. Front windows both sides not going up and down as they ought. Occasionally they would work....sometimes I'd have to grab the glass and pull it up, then activate the power window button to hold it up..........pulled door panel apart......found problem almost immediately. There'* this plastic piece in a trac that runs the length of the bottom of the glass. A small metal connection kinda round ball that I determined was to go into one of the 2 holes in the plastic piece. Got a screw driver, lined it up, gave it a soft wack with a hammer......in it went.............wa--la.......window fixed....working as it ought. Now, if it came out once...who knows why....how do I keep it from coming out again? Looks to be a really poor design......and plastic to boot.

The plastic clip develops a crack in the middle, allowing the ball to jump out. You have to replace the clip in order to prevent it from happening again. The same clip is used in almost every GM product.