MB will mark P/N's on almost all the rubber parts, but not on any of these turn signals.

Well I did get the thing fixed (replaced) this morning, and I've figured out about 6 different variations of these things. Four of the variations can be spotted from the outside. These are:

Chrome stalk; 2 speed selection wiper (no intermittant)

Black stalk; 2 speed selection wiper (no intermittant)

Chrome stalk; 3 speed selection wiper (w/ intermittant)

Black stalk; 3 speed selection wiper (w/ intermittant)

The last two are more difficult to ID. These involve the contact config at the rocker switch at the end of the stalk which can't be seen from the outside; you have to remove the square handle at the end which is pretty easy to do. You drive out the ~1.2mm diam pin that is barely visible from the outside and runs thru the square handle and keeps it from falling off.

Anyway, apparantly there are some later versions that have two pairs of contacts in that end switch. This is the variation that I got from my friend Rudi who had a box of these turn signals. The only problem was the missing P/N's on all of these. Well the result of putting the dual contact rocker part in my car that was only supposed to have one pair of contacts was that it supplied power to the wipers in BOTH switch positions, i.e. the wipers could not be shut off. We didn't figure all this out right then, but I did a little later when I disassembled both units side by side.

What is totally amazing by todays design standards is that I was able to easily remove the single pair contact rocker end from mine and put it into the twin contact new switch thus removing the undesired 'auxiliary' power path. To do this I had only to push out another 1.2mm pin that acted as an axle for the rocker. The rocker for the wiper speed switch was also of the same design; easily disassembled.

So the good news in all of this is that these early versions of the turn signal switches with the cast pot-metal cam-slots are so rebuildable that the enterprising mechanic can make something work with a visit to the 'graveyard'.

In my case I actually got a new turn signal. Rudi has just flagged it years ago with a tag that said "Turn Signal Switch?" so he had probably run up against the same thing as I saw, we just didn't figure out the 'why' until today.

What amazingly workable designs! When I looked thru that box of turn signal switches, I was amazed at how many common parts there were in all of these. The only real differences have to do with the number of switch contacts, but as I said, you can mix & match these.