I just replaced the alternator on my '82 240D. My digital voltmeter shows 15 volts when running. Is that too high? A previous owner had already replaced the alternator--not surprising in a 21 year old car. But somewhere along the way, the wiring was changed. I have three wires--two (2) larger diameter in woven jackets, but the color is hard to tell--it might have been red, but not it just looks brown. On my old alternator, these went to a common post inside the place that is shaped for a plug--but the post is by the side labeled "D+". I think was due to a non M-B repair. The third wire is much smaller gauge ( maybe 18ga) is blue and was screwed to a terminal on the alt body---it is too dirty to read any label on that terminal..
I think the two big wires go to terminals B+. The third can either go to D+ or just "+". Is "D+" german for idicator light?
Which terminal should it connect? I have it on the "D+" but am worried that the volts are too high. Of course that may be due to an undersharged battery.
I am just looking for some confirmation before I forget about it.

I would say 15volts is a bit too hot. Most MBs seem to run about 13.8volts which is a bit lower than the standard 14-14.4 seen on most vehicles. I think you will be okay for a short while but you may start boiling (overcharging) the battery in time. Run it for a day or two and recheck the voltage. Regarding the wiring I always am willing to let an electrical specialist take a look at things like this. They know far better than anyone, even the standard MB shop mechs, what is going on with electrical systems. RT

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Voltage has dropped down to 13.8 to 14.1 based on load. I checked it last night after a couple of short runs.