Hi

Yes the 3rd and 4th postions are for marker or parking lights (or "side lights" as we call them in the UK).

This is so you can park your car legally in Europe (again in the UK it's illegal to park without lights on an unlit street or within 15meters of a junction at night and in Europe variations of this apply) and the reason there are 2 postions is so you can switch left or right lights on to park either side of the road (also allowing for the fact that UK and Europeans drive on the opposite sides of the road) without too much drain on the battery.

As "Sublettd" indicated, the 0 1 2 3 rotary switch is a fairly standard European function for raising and lowering the headlights (main beam and dipped) to allow for varying loads, but I believe (from previous threads on the forum) that as this is not legal in the US so I guess this was disconnected when imported (if it was brought in and modified "properly"!) - if not be careful you don't get a ticket for dazzling a traffic cop!

Cheers

Jim

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Keep your Motor runnin'

Jim's '88 300SL