4G alternator wiring

[LittleBeefy]

https://flic.kr/p/2siNwSE
I’m trying to figure out my 4g alternator wiring conversion after swapping on the Explorer serp. After removing my voltage regulator and the connector I am left with three wires. I know the green one in the middle connects to the alternator plug. What about the other two? The long one on the left (black and green stripe maybe) used to go to the positive on the alternator and the one on the right (black with a yellow splice) used to go to the voltage regulator and the starter solenoid. What do I do with these two wires now? FYI this is a 76 Bronco.

 

[dmoses42]

Check this out.
https://www.supermotors.net/registry/media/870470_1
It says 1g to 3g at the top, but if you read the notes below the schematic, it says "or 4g". This is what I've been studying, but I will be going 3g when I change, for now.

This is from Steve83 on here.

 

[LittleBeefy]

Thanks. I read it earlier but I don’t understand how to apply it because all I see is 3 wires coming out of a single round connector.

 

[dmoses42]

Do you have the plug for the 4g? On the schematic, the yellow from the old VR goes to the A post on the new alternator, the Green/Red goes to the Green/Red on the I post on the new alternator, the fat Black/Yellow gets capped off, not used. There is supposed to be a Black/Red that I think was a ground (mine had been chewed off or something) gets capped. Then you use 4 Gauge cable from the B+ post on the alternator that goes through a 175 amp Mega fuse, then to the positive side of the starter relay/solenoid. The yellow from the old VR should still be connected to a larger black wire, and the other end of that should have a fusible link connected to the positive side of the starter relay. Hope this helps. Someone else will likely post up more clearly than I did.

 

[Oldtimer]

Your "single round connector" is connector C-206 on the below schematic (thnkx to @SeaBiscuit68 ).

These are schematic color codes. Actual found in Bronco may be different colors.
BK-Y = black yellow stripe wire
BK-R = black red stripe wire
GR-R = green red stripe wire
Y = yellow wire


A) The "long wire on the left (black and green stripe maybe)" is circuit 37, BK-Y wire, and was the charge wire from the alternator, thru ammeter loop, and back out to battery as circuit 38, BK-R wire.

B) The "wire on the right (black with a yellow splice)" is circuit 38, BK-R wire. It was spliced to BK-R fusible link connected to battery post of starter relay, to supply power to Bronco. This splice also contained circuit 152, Y wire, used to supply battery reference voltage to regulator.

C) The "green wire in the middle" is circuit 904, GR-R wire, is key ON power used to activate the voltage regulator.

What to do with these 3 wires.

A) I would cap it off, as stated by dmoses42. It is a constant 12v from battery.

B) This is the 12v supply wire (10 gage) to Bronco. It needs to be connected to battery. I would connect it to the battery post of the starter relay, thru a suitible sized fuse/circuit breaker/fusible link. It supplies voltage to Fuse box, Ignition switch, and Headlight switch. Not sure about the yellow wire that went to regulator. I would remove it, unless 4G alternator needs battery reference voltage.

C) Connect it to 4G alternator, for turn on circuit.

 

[DirtDonk]

Not sure about the yellow wire that went to regulator. I would remove it, unless 4G alternator needs battery reference voltage.

It still does, just like the 1, 2, and 3G alternators.
So the old Yellow from the voltage regulator (full 12v at all times) connects to the new alternator's Yellow w/white stripe wire in the connector. This is the "A" wire as mentioned by dmoses.

So to reiterate what they already said:
Green w/red "old" to Green w/red "new"
Yellow "old" to Yellow w/white "new"
Black (don't care what color trace/stripe) remains connected to the battery side of the starter relay. It's already there, so leave it alone or nothing else will work.
Other Black that used to connect to the back of the alternator is either:
1. Capped off and tucked away for later use.
2. Cut off at some safe point and taped up inside the harness. (not as desirable).
3. Used to power a separate fuse panel.
4. Similar to #1 it can simply be connected to the battery side of the starter relay, along with the other Black wire.

A side note, if you're ever messing under the dash an decide to unplug the ammeter wire, don't!
Leave it connected to itself even if you're replacing the ammeter with a volt-meter. Just like leaving the other Black wire off of the battery terminal, separating the two sections of Black wire behind the instrument cluster will kill all the power to the truck.

Paul