If your sec is the same as my 90sdl, the easiest way to have a good look at the switch would be to pull the instrument cluster. You can make the tool, buy the tool, rent the tool, push the cluster out from behind (have to remove panel under steering column...or
Stick a small screw driver from the front sides and pry the cluster out. You want to put something on the soft porttion of the instrument cluster surround not to mark it. YMMV work w/ CAUTION...I did mine this way 2 days ago.

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82 300D....went to MB heaven
90 350 SDL....excercising con rods