Wiring question - 76

[Knuck]

I am in the process of swapping in a 5.0 that has an Alum March style serpentine setup. It uses a 3g Alternator that has a self exciting regulator. So with that, I removed the factory regulator and wiring. I am left with the factory connector that has 3 wires. a Black with Red Stripe, a Black with Green Stripe, and a smaller green and red wire. From my reading, the small green red goes to the alternator warning light on the dash. My question is, now that the regulator is gone, do the other 2 larger wires get connected to the positive side of the starter solenoid?

Connector

Wires

 

[904Bronco]

If it is truly a self exciting Reg on your G3 then all you need to do is hook the Batt lead to the Bat or starter relay (+) post.

It has been a while since I played with a factory harness...

The green/red stripe wire is the field wire to the alt > hot with Ign/run only. It should not be needed and I am not aware of a warning light on a factory Instrument cluster/dash.

The other two wires are power back through the Amp gauge and then to the harness. I don't recall which is which, perhaps someone (Dirtdonk) will speak up and share his wisdom

 

[DirtDonk]

Do you have a picture of the remaining connector? If the black wires are female, then there is nothing you need to do other than perhaps cover the openings with some things so that the connections don’t rust.
Any male contact points on a connector would need to be completely covered and protected from shorting out on something.
As 904 said, the one black w/red wire should be a larger size, is still connected directly to the battery via the ammeter loop. So it’s going to have to be protected.
One of the methods used to protect it is to add a ring terminal and connect it, like you suggested earlier, to the starter relay.
Not sure what a black with green stripe accessory wire is doing out there, but perhaps it’s a 76 thing.
I’ll check Diagrams later, but it should also be protected.

As said, no indicator light on a bronco. Only a gauge. So the red with green stripe wire had a completely different function on vehicles with amp gages rather than indicator lights.

 

[DirtDonk]

Did the alternator come with the serpentine system?

 

[Steve83]

1-wire alternators are known to be twitchy. If it gives you any trouble, install a normal 3G regulator. Refer to this diagram, and KEEP all the factory wiring in case you need it. Either tape the unused wires into the harness, or go ahead & bring them to the 3G 1-wire regulator connector so they're there if you need to replace it with the standard (more-reliable) connector. You could just install the normal connector now. If the regulator doesn't need them, it won't use them, even if they're connected.

(click this text)

 

[Knuck]

Links to the pictures of the connector and wires are in my original post. The connector is a female connector. The alternator was purchased separately from the Serpentine Kit. Its from an 89 Mustang GT. The serpentine kit is designed to use that style alternator.

 

[DirtDonk]

Thanks. Didn’t even pay attention to the links.
So where did you get this mustang GT alternator? Right off the shelf at the auto parts store? Online supplier? Got a picture of the connector for the alternator?

Just trying to determine if it is in fact, a one wire alternator.
Internally regulated, and one-wire alternators are two different things.

 

[Knuck]

Its an off the shelf alternator for and 89 Mustang GT with 5.0. Got it from Advance Auto Parts. Alternator has 2 connectors 1 is a 3 pin the other is a single pin. Single pin is a stator connector I believe. Here is a link to it at American Muscle.

3G Alternator

The 3 pin and 1 pin connectors I got from Amazon.

Connectors

I found a link somewhere. Cannot find it now. But you take those 2 connectors, and the yellow wire on the 3 pin connector connects to the alternator output with the 4ga connecdtor. The white wire on the 3 pin connector connects to the single pin stator connector. The green wire on the 3 pin connector is a Tach output from the Alt. Right now, my engine is on a stand alone power harness as I am using a Microsquirt ECU and a HotRod 5.0 harness from EFI Source. Now I just need to get power to the rest of the factory Bronco harness.

 

[DirtDonk]

So it’s not really a one wire alternator.
You will need the old green with red wire after all. The green with red wire on the new alternator has nothing to do with a tachometer. Or, in the case of a bronco, an indicator lamp.
It has everything to do with the alternator working, however, so you need a 12 V source to excite the regulator.
And that’s the green with red wire from the ignition switch. It’s hot in the ON position only, and not the ACC position.

Connect your old green with red wire in that old connector, to the new green with red wire from your alternator connector.

 

[Knuck]

So it’s not really a one wire alternator.
You will need the old green with red wire after all. The green with red wire on the new alternator has nothing to do with a tachometer. Or, in the case of a bronco, an indicator lamp.
It has everything to do with the alternator working, however, so you need a 12 V source to excite the regulator.
And that’s the green with red wire from the ignition switch. It’s hot in the ON position only, and not the ACC position.

Connect your old green with red wire in that old connector, to the new green with red wire from your alternator connector.

Thanks, And what about the 2 larger wires from the female factory plug? Do they both go to the positive side of the starter solenoid?

 

[Steve83]

Thanks, And what about the 2 larger wires from the female factory plug? Do they both go to the positive side of the starter solenoid?

Did you look at the diagram I linked? It shows exactly what to do with each original & each new wire.

 

[Knuck]

Did you look at the diagram I linked? It shows exactly what to do with each original & each new wire.

Sorry, I missed that. Ok. So the bigger black/red gets connected to the Positive side of the Starter solenoid with a 16ga fusible link, and the green from the Alt Harness gets connected to the small Green/Red from the harness. Sweet. I think I can handle that. lol

 

[DirtDonk]

And luckily, the way that connector is designed, you don’t really have to do more than say, apply a little silicone to the open connector for the other black with yellow stripe wire.
Since it’s a female connector, it’s not really in danger of shorting out unless something strange pokes into it. And a bit of silicone will keep it safe and rust free for a long time as well.
In case you have to use it for something in the future.

 

[Knuck]

Ok. I wired things up as mentioned above. No power when I turn the switch. And honestly, I pretty much stopped after that because, 1.) It was getting cold in the shop. 2.) Was late in the day. 3.) Was beer thirty, so I have yet to check things with a meter or test light. So I have to have missed something along the way. I am working with a 76, so not sure if that is in play here or not. Here is the 75-77 Power Distribution Wiring Diagram. I wired things up per the 3g Alternator Swap Diagram on the same site. I have my engine running stand alone outside the Factory Harness, and need to get power back to the ignition switch so I can then connect up my keyed 12v for the EFI, and o2 Sensor harnesses. Its not helping that I started this EFI engine swap 2 1/2 years ago and am just now attempting to finish things up. Any help would be appreciated, as I am at a loss. Will continue tomorrow by poking around with volt meter, and test light.

 

[Knuck]

Update. Stupid headlight switch fooled me. Test light says there is power to the switch, and I do have headlights and dash power,so all should be good. One question, I do need a Switched +12v source to use as a trigger for the ECU, and O2 Sensor harnesses. Would the old black/yellow that went to the old voltage regulator be suitable for that? ECU, and O2 sensor controller are in the glove box, so using that for the trigger would be extremely convenient.

Sent from my SM-S901U using Tapatalk

 

[Oldtimer]

The old black/yellow went to the alternator, not regulator, and should be hot all the time.
It is connected to the black/red wire (near ammeter) that is connected to battery post of starter relay.
The green/red wire that went to regulator would be perfect for ECU power. It is 12v in run and start positions of ignition switch.

 

[Knuck]

Is the black/green hot when the key is in the Acc position as well? Not sure I want power to either the ECU, or O2 Sensor when the key is in ACC. I will have to check that tomorrow to make sure.

 

[Oldtimer]

Black/green has power in ACC and RUN.
Great to listen to radio when parked (ACC) or when driving (RUN).
Not great for ECU, and electric fuel pump, as the power is disconnected from black/green wire when key is all the way over to START.