1990 Lincoln Towncar

There are 3 nylon pins in the drive end of the motors that shear if the window binds for some reason(lack of lube in the window runs, a persons arm in the way of the glass, etc). Later Town Cars used a cable driven regulator that was somewhat trouble prone, I don't remember if the 90 used it or not. Remove the door trim panel and the vapor barrier. Remove the speaker, In the door shell, there are 3 gimples directly in line eith the boltd holding the motor to the regulator. Drill holes at the dimples with a ~3\8 drill bit. Remove the 3 bolts (5\16" heads) and pull the motor out through the speaker opening or other available opening. The nylon pins are replacable, but at 15 years, I would suggest replacing the motors.

Here's a link to a Tech article outlining the procedure.