No wires going to the left rear fog bulb opening....nor is there a socket itself.
Just bare metal hole to accomodate a socket.
I found a new bulb that was loose rolling around inside the left fog lens, which led me to believe it was a spare after not finding any sort of electrical wire or contacts.
Anyway, the same story for the right side.
After fishing out the bulb I tried to plug it back in the hole but it doesn't hold well, which leads me to believe the previous owner thought it would be a good place to keep a spare and not MB's original intention.
By the way, this is a 81 300SD.
I don't think it was legal in 81.
My '85 volvo wagon has rear red fog lights on both sides and is kindof obnoxious if there isn't bad weather to cut down on the intensity, so it works when appropriate.
But back to the Benz talk...