So, a mystery to wake you up ! 04, 2 dr. blazer elec pass window, works fine in the driveway, though finishes the closing with a slight bump at the end of travel....not really noticeable, but different than the clean travel on the driver side. Get on the highway at 70 or so....put the window down and then up....runs smoothly til the last 1nch or two...hesitates and then a let-loose BANG and closes tight. And I mean a BANG. This guy must be hanging up somewhere til the motor overpowers and the hand up lets go.... Am I on the right track ( no pun ) and anyone know definitively what may be the issue. I can't believe it is the regulator per se . Thanks for any assist. Dave

 

Could be the pop rivets that hold the motor on are loose/missing. Loose is a common problem. Could be one of the brackets to a window track is busted. Pull the door panel off and get looking.

 

When I'm going down the road at 80-85 mph and I roll up my windows, they will pop also, Its always done that (2000 LT 4x4) I think its just the vacumm that is created. When at slower speeds everything is fine except once in a while my driver side window will not work, I just kick the side panel if driving or open and shut the door and its off and running again. I figure a bad spot on the drive motor...

 

Thanks for the hint, but think both windows would be a problem. Hope someone can really help here........it is really scary when it frees up with a monster bang !!

 

take your door panel apart!!!! we cant diagnose it from guesses.