Alternator wiring diagrams: 1G, 2G, and 3G

[87gtVIC]

Yes do that please. The yellow wire originally (on my car) traveled back with the two fat charger cables and eventually spliced into them through fusible links. So if you removed the ring terminal from the starter solenoid that was originally for the alternator you removed the voltage sense wire.

For god sakes..white/black wire from voltage regulator to spade terminal on the alternator. Yellow wire to the charge stud and red green wire connected to the stock red/green wire.

damn daryl beat me to it.

[BerniniCaCO3]

Thanks.
I didn't miss this... just seemed clear that it must end up back at a hot anyway, why make more work for myself?
Testing it now

[BerniniCaCO3]

huh, nope, no change. The battery's dropping, of course; so right now the battery reads 12.5x volts, and when I turn the car on, and the alternator is running, it drops to 12.2x volts. Back to 12.5x volts once I turn the car off again.
Voltage is going to "charge" the alternator, rather than the other way around....

Could the alternator tester at the auto parts store have lied?

[hypostang]

It could have , I would just double check that you have everything wired correctly , is so take it to a different store and get it checked .

[BerniniCaCO3]

I've got the green cable left in the original 2g harness, left alone.
I've got the white wire looping over to the small single-wire harness that's only on the 3g-- not there on the 2g.
I've got the yellow wire going over to the charging cable now.
I've got the charging cable going to the battery.
Just for good measure, I added a fat ground wire on the back, but shouldn't have been necessary.

Honestly, it doesn't seem that complicated. The above is all correct, right?

[hypostang]

So it looks exactly like this


If so you are correct, and just to clarify your green wire is connected to the car right ?

[BerniniCaCO3]

green wire disappears into the original wiring loom, wherever that may go (in theory somewhere in the dash)

[sly]

does the voltage change with engine revs? if not, could be bad continuity in the charge cable or a bad voltage regulator.

[1987cp]

Have you verified that the green wire is still providing key-on power? If not, feel free to tap it into any key-on power source.

[BerniniCaCO3]

When the key is in the on position --starter not yet engaged, but power is there to all the dash lights-- I should have 12V on that line?

[sly]

"should" yes. If not... there's a problem. Check the wire harness connections on the driver fender if there's not 12V there. I think there's one or 2 harnesses inline to the alt.

[BerniniCaCO3]

Hahahahahaha, sorry guys for all the posts... figured it out.
So, once I'd rechecked my wiring for the dozenth time, I mean come ON! The 3g upgrade is not rocket science, and I was getting really frustrated.
Your posts and photos confirmed I'd definitely had it correct.

So finally I take the alternator to pepboys and have it retested. I'd tested it at salvos last month, what could possibly have changed sitting in a bin...
And as it goes down the test, the results for voltage: FAIL regulator: FAIL diodes: FAIL.
Heh, well that explains that.

As I walk back to the car, planning my next trip to the junkyard but pleased I'd figured it out, I notice something.
I'd gone ahead and replaced the brushes for good measure.
To install them, there's a pin that holds back the springs. I'd sworn I'd removed it, but i think I switched regulators from a rebuilt one back to motorcraft at one point.
It was still in there.

The brushes never had contact with the alternator!
I take it back in to pepboys, borrow a pair of pliers, pull the pin, test it, passes: put it on the car, and 15V. Whew!

[hypostang]

Glad you got it figured out ..and I promise i did not chuckle

[sly]

rolling on the floor laughing however...

glad you got it sorted. at least it ended up being simple.

[BerniniCaCO3]

oh, feel free to. I did-- what else can you do after wasting hours uninstalling, rewiring, reinstalling an alternator only to find out it was a stupid little pin I'd forgotten to pull?