change driver side window regulator

You will need to contact the Buick dealership to ask them. I know many newer vehicles, such as Chrysler/Dodge, for example, have gone to a motor-regulator set-up which is not repairable. In one instance, a customer broke a tiny plastic clip in his Durango, causing the window to go down, by leaning on it. We ended up replacing the entire motor/regulator assembly because it was not field-repairable. This may be the case with yours, also.

I have a 98 century and have the same prob with the rear pass side and cost me around 150 for regulator and close to 80 more the have it done.