The battery to my '84 300TD died. Autozone checked it:
they said the battery was fine but the alternator wasn't charging it.
Took the alternator out and checked it alone--it's fine.
So I suspected the electrical wiring hooking up to the alternator.
Checked the wiring bundle carefully, but saw no breakage.

I did find something suspicious, however.
A single wire branches off the bundle,
and it wasn't attached to anything--it was just hanging loose.
It looks like it might be a ground wire--
it has an O-shaped tab at the end you could bolt down.
Anyone know what it is?
I'd like to avoid testing out the idea that it's a ground wire;
if it's not, I don't want the battery dying on me downtown.

Thanks.

 

thanks for the reply. =)
I see a bundle of three wires that plugs into the alternator;
a blue and two dark oil-blackened cloth-weave ones.

The loose wire is a fourth wire. It's faded black.
It has a blue sleeve crimped onto the end
(just below the O-shaped ring).

I'm inclined to think it's a ground wire.
They wouldn't run a ground wire into the plug that goes into the alternator, would they?

 

I don't know what that fourth wire is. But, I would check your battery ground cable to make sure it is in good condition and you might consider replacing it as a prophylactic measure since they are rather inexpensive.