W126 door panel, I remove the little black trim behind the release lever with a small pocket screwdriver, then remove the phillips screw and the chrome trim plate. Then remove the two screws holding the seat switch in and remove the seat switch before taking the door panel off. If you tip out the chrome trim then you can get to the large phillips screw is up under the top of armrest grip. Be careful installing this screw because it is easy to cross thread it and wreck the speed nut! Then you have to take the panel back off.....

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