I fixed the same problem on my 2003. GM said I have to change the regulator. In fact all's i had to do was change 2 plastic clips that run on the window slides.
1/ take off the inner door skin. and remove broken clips,
2/ gentley snap on new plastic clips, re conect wiring to ensure it works before putting door skin back on.
Chances are you don't need a whole regulator (window mechanizum that enables your window to go up and down)
The way that replace a window regulator in a 2003 Buick LeSabre front drive side is by removing the door panel. Next, disconnect the electrical connector on the regulator and replace.
5w30
Take your door panel off and replace them...
How do you replace rear lift gate unit on 2004buick rendevous
what is a etc sensor for a buick rendevous
under the dash on the driver side
check your owners manual i belive its 5 quarts
Most likely it is the regulator, either the cable is broken or the plastic at the top broke and the cable became unspooled and wrapped around itself. The window is held in by two screws that tighten a clamp on the window that holds pretty tight so it is doubtful it is that.
If the window regulator cable has failed, the entire regulator will have to be replaced.
#14 in center console pasenger side near floor ...thats where mine is in 2002
the cable is frayed ,you will have to replace the window regulator motor assy.
You will have to replace the regulator assembly.