Explorer swap charging system question

[1973bronco1973]

I have the explorer front dress and used the factory explorer alternator harness, so it may not match yours. The yellow wire I am touching I wired straight the battery. The other wire is hot when the key is on. I

do not have any factory dash lights to tell me when the alt dies. Of course the large wire is to the battery as well. 10 years and a few thousand miles and no issues. Hope this helps to find what wires you need from your harness to go to the alternator.


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[EFI Guy]

I do see the harness wire labeled 'alternator warning light ground. other side of bulb is hot in run' that is green and red, but I havent wired that in yet because I wadnt sure how to wire it up correctly.

You would power a warning bulb with ignition hot. The wire you have there will ground the bulb to illuminate if there is a charging problem. The ignition hot also feeds through that bulb to energize your alternator.
The bulb is optional. You can just wire that wire to hot in run or the existing green/red in the Bronco that originally fed the voltage regulator if you don't want the warning indicator.
Also optional is a 560-ohm resistor wired in parallel with the bulb. This will ensure the alternator still charges if the bulb burns out.

Note: Your check engine light, overdrive off light, and overdrive switch are all wired the same way. Provide ignition hot to them, connect the wire I provide you to the other side of the bulb or switch. There is very little draw involved here. You can use the same circuit to power all of those bulbs and switch. A 5 amp fuse is plenty adequate.

 

[DirtDonk]

Sorry if I missed this, but what is your main vehicle harness? Is it all original wiring, or do you have someone else’s replacement harness for the Body and chassis?
If original, there should still be a green with red striped wire under the hood. It used to switch on the old fender mounted voltage regulator.
If you can find that, connect it to your Alternator, and that will take care of almost everything.
After 74, there might have been another one over on the driver side to power, the ignition control module. If you no longer have a factory ignition, you could use that too. But I’d rather use the one originally meant for the Alternator if available.

As the others have said, you still need power to the green with red wire to get the alternator to work.
You do not want power when the key is in ACC position, but the existing circuit on the Bronco switch that has wires hot in the ON position only, is the green with red wire.

 

[Bruners4]

What I'm seeing in the Ford 2001 wiring is that the fuse is feeding Battery positive (+) to one side of the Charge Warning Light when the ignition switch is in the Start or Run position. The light is now looking for battery negative (-) to allow current flow through the light to elluminate it. The Green/Red wire is connected to the Alternator (Alt). When the Alt is not spinning, this Grn/Red provides a path to battery negative and the light is on. This current also energizes the rotor creating a magnetic field that is used to create current in the Alt. When the Alt is spinning and has the rotor energized, it will begin to create current and voltage to run the vehicle. It also changes the Grn/Red wire voltage to equal the charging voltage. The Charge Warning Light now goes out as there is battery positive voltage on both sides.

I don't have a wiring diagram for a Ford externally regulated Alt readily available, but the Charge Warning Light works the same on many charging systems.

 

[DirtDonk]

Yep, same for the old style alternators.
However, Ford had two ways of wiring those in the old days.
One was used with a warning lamp (4 wires in their original positions), and the other was used for vehicles with ammeters (3 wires partially reoriented) instead of a lamp.
By the time internally regulated alternators became the norm, ammeters were either out, or rapidly on their way out.
In either case, the warning lamp was used on the green with red wire to what they refer to as the “I“ terminal of the regulator.
Same for internal and external regulators alike.

 

[76Bronko]

Thank you everyone for the help. I found the original green and red wire that went to my coil and hooked that up to my EFI Guy harness..And the alternator started charging and putting out 14.5 Volts!

I appreciate you all for taking time out of your days.

Mel