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Old 08-03-2002, 03:54 PM
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We bolted THREE wires to the alternator?

For those who've heard THIS tale of woe, forgive me, but I've yet ANOTHER problem I could use some mechanical wisdom to solve.

The "new" '72 220D has another slight problem. There are three wires going to or coming from the alternator and to stop the alternator light from glowing "we", I guess, twisted these 3 wires together and affixed them to a bold either on the alternator or voltage regulator. Why would "we" do that?

Is there a wiring schematic on the internet or that I, a novice, can decipher. I know the wires go somewhere else. BUT, WHERE? The wires can be seen if looking straight down behind the radiator, on radiators far left side. It is situated so that when the tire is turned to the right that it can be seen through a hole looking into the engine area from the tirewell.

I think these 3 wires have something to do with my battery discharging so quickly. But, I could be wrong.

And since I'm fairly sure I don't know what I am talking about here I recognize it's extremely difficult to clearly, intelligently, even get my question asked... I hope I can make SOME sense.

As always, any assistance appreciated!! (ASAP, please, as I have to head out early in the morning).


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Old 08-03-2002, 04:07 PM
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Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
You have, on the back of the alternator, a plug with three wires (these go to the voltage regulator on the fender, passenger side, rectangular box) and the hot wire, which has a separate connection. There is also a ground strap (usually frayed off by now) from one of the through bolts to the bracket or engine mount.

If you tied the three wires together, you are grounding the rotor, and will drain the battery. Certainly, the light will go out, since it is no longer connected, but now the alternator isn't, either.

The usual reasons the light won't go out are missing fan belt or dead diodes or brushes. If you can still re-connect the wires to where they were (each wire has a differernt color), you can take it to a battery shop and have them test it. You might just have a loose belt (if so, I can give you instructions on tightening it), but you may also have a bad alternator. It is, after all, thirty years old! You must re-connect the wires properly to get the alternator to work.


The alternator is on the passenger side.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
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Old 08-03-2002, 04:27 PM
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The alternator was rebuilt just prior to my taking over the car. So it's age shouldn't be large factor.

Left. . . my left as I stand in front of car's radiator looking back at the engine area. You're right about left; we usually refer to the driver's point of view: and from that perspective, this mysterious mess of wires is actually to his RIGHT.

Anyway, these wires don't seem very long, certainly not long enough to be routed anywhere else without splicing on a length of wire. BUT i WILL and i can, especially if you think of me as a very enthusiastic 8 year old or something on that order.

I KNEW my dead battery and these wires were the culprits!!

Oh, boy! I'm getting closer!! Thank you, Debbie

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