what does this happen NOT using express mode?

 

Yes. If you just hold the switch down (instead of using express) the window goes all the way down, and then doesn't hit a solid "stop" like it should. Instead, it goes too far and the regulator gear pops off. Now, of course, if you let go of the down switch before the window goes down too far, all is good. I just took the passenger side door panel off to take a look at it....and there doesn't really seem to be a hard stop mechanism. It seems more like it's the regulator that basically reaches a certain position where it won't allow the window to travel down any farther. Does that sound right?

 

i have read lots of postings about window regulators and windows going down too far but i have not seen any references to the Window Regulator Stop. This is a white plastic piece that screws into the extra hole in the middle of the regulator bottom bar, the one to which the window is attached. this $8 piece extends about 2 inches below the bottom of the window and hits the inside bottom of the door to stop the window from going down too far and the gear running off the track. it is not visible in the pictures above but the hole it screws into is shown. On my car, someone installed this stop upside down so it was useless and so now i am replacing the broken regulator and reinstalling the stop properly. i suggest also that an old regulator motor might draw too much current under normal circumstances for the ECU to properly detect the current surge that causes it to stop the motor at the top and bottom reliably causing regulator failure. this would suggest that a new motor is eventually needed.