First check that the switch is okay. If you have to remove the door panel, it's something like this:

- pull the lever as if opening the door from the inside
- pry off the plastic cover behind the lever
- remove the screw behind the plastic cover
- pry off the lever trim and slide it down the door handle
- pry off the seat control panel
- disconnect the wire terminal
- remove the upper door handle screw
- remove the two lower door handle screws
- remove the door handle
- remove the striker chrome trim
- pry off the door jamb light
- disconnect the wire terminal
- unscrew the door lock button
- lift the door panel a couple of inches; be sure to clear the lever
- the door panel should be free of the door

I don't think there is any window trim in the way in the front doors.

Peel the plastic off carefully so you can reuse it.

When reinstalling the door panel, make sure all the clips go into their pockets and align the door lock rod with the hole.

Sixto
91 300SE
87 300SDL
81 300SD