No, of course the part numbers are not the same. Remember the W123 switch will always have atleast an extra pin because 123's have the windshield washer pump, W115's have the foot pump.

I removed a turn signal switch from a wrecked W123 1983 300D Turbo and put it in my W115 1976 300D and it works great. No reason to hunt down the ultra rare 73-76 W115 switch when a W123 switch works fine and its MUCH easier to find.

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1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg