OK so a month or two ago my passenger window quit working..no up, no down..nothing.

I ordered a new motor and regulator and put it in. Everything was great for about a month and suddenly when rolling it up when it got to the top and should stop, instead of stopping, it would start grinding REALLY loud inside the door. So I figured gears must be stripped or something...about 3 more times using the window and then it wouldn't even go up without making the horrible grinding sound, so to raise it I had to force it with my hand as I pressed the switch.

Ok..fast forward and they send me a new one being it was under warranty and I put the new one in about a week ago. Everything worked great, until today. SAME problem!

Now here is what I don't get, the last one after I took it out of the door I decided to be Mr. Investigator and find the problem. I tore into it to look at the gears and nothing was stripped and it all looked just fine, so that made me scratch my head as I don't understand what could be going wrong.

Now that it has happened again, I'm not happy. I am going to take it apart once again, and check, but is there anything else that could be causing this? Like for some reason there is something wrong electrically that doesn't stop the motor when it is all the way up, which then causes the gears to come out of alignment due to all the stress or something?

I can take a video so you guys can hear the god awful sound if I need to...I am getting sick of taking this door apart.

Could be a problem with the control.

Is there any way I can test to see? I know it is unlikely that it is anything other than the motor itself..but I really don't want to have them send me yet another, and have to send this one back and put a new one in only to have it go bad in a month again. Maybe it is just possible I coincidentally got two bad units in a row I suppose.

I'm planning to tear it apart this weekend to see if I can find any missing teeth..if anything I will start with swapping the gears from my old factory unit into it, as I never had a problem with them.

I guess we will see what I find out

I've never tried testing one. Not really sure how it can cause a problem. But the chances of two bad units although possible, is unlikely.

My Sis'* bonne has had this same problem for a LONG time. The previous owner (who worked at a GM dealership[neighbor]) Tried and Tried to fix it. no luck...but this is a common problem with the bonneville and your not the only one. confuses the hell outta me to...

The window alignment might be out causing it to bind, or there may be an issue with the mechanism causing it to have high resistance to moving. Pull the motor off, and try moving the glass/mechanism up and down by hand to make sure everything is moving smoothly through the entire range of up to down. Adjust glass alignment and/or lubricate the mechanism until everything moves smoothly by hand. Its an inexpensive way to eliminate one possible source of your issue.

That was one thing I thought could be a possibility, as it is the only thing that user error could be causing. Maybe I have the glass in the rubber holders/grooves that hold it slightly tilted or something.

We shall see what I find out this weekend.