Green/Red Wire from Voltage Reg.

[DirtDonk]

Ok, while I wasn't seeing the pic during my reply, the "black box" you mention should be the voltage regulator. I thought you might have meant the relay (black) or the fuse holder (also black) but now that I look again, I see your regulator is black also.
So you're mostly good.

Which alternator are you using?
If you have not upgraded to a more powerful and perhaps more modern alternator, I would consider doing so.
The aftermarket EFI setups may not be as sensitive to things as the factory bits are, but I have a feeling they are still going to like a full voltage maintained whenever the engine is running and you don't want the EFI to cough and sputter when you turn the heater and headlights on!

If you have other accessories that draw power, this is even more important.
So if you keep the original style alternator it should be at least 65a rated, and preferably more. Like in the 70-100 amp range.
That's why the modern internally regulated alternators like the 3G are such popular swaps these days. Easy way to get 95 to 130 amps and more of nice steady power.

And you'll be right in there with the new charge wire running directly from the BAT terminal of whatever alternator you use, to the battery side of the starter relay.

And speaking of that, I did not go into detail about that new charge wire before.
As you suggested, running a new charge wire from the BAT terminal to the battery side of the starter relay is a good idea. Makes the run nice and short with fewer potential problems.
But don't undersize the wire either. Even with a small alternator you should be using at least an 8ga wire. If you go with a 3G instead, go to a 6ga battery cable size wire.

This is not because 10ga can't handle it, because it actually can. But the larger wire helps to guarantee a better, more uninterrupted supply to the battery and to the electrical system.
And if you upgrade to a more powerful unit you will already be ready for it if you go with a larger wire now.

Paul

 

[DirtDonk]

Just re-read the part where the original Green w/red wire was disconnected but that you (or the PO) had substituted another wire for power.

Even though we talked about it last year, let's run through the connections for the regulator in order again.
For the moment, forget about wire colors! Since they've changed so much since the vehicle was new let's use the position and check the wires for function.

Remember that in that 4-wire connector there are only 3 positions that are actually utilized. They are marked I A S F on the regulator. Or F S A I if you're looking at it from the other direction. You are only going to use F, S and A now. As far as you're concerned, the I does not exist.
You can usually see these markings on the snap-lock part of the regulator.

F - wire runs from the F terminal directly to the alternator's FLD terminal.

S - wire runs from the S terminal directly to the ignition switch's ON only terminal. You do NOT want this wire energized in ACC.

A - wire runs either directly to the battery as you had it last time we talked, or anywhere that's convenient that has battery power all the time.

That's it. No fourth wire, no other functions, nothing else to do with this.

Paul

 

[Crainbow243]

The BAT is the large Black w/yellow and no, it does not go to the battery like it would on vehicles without an ammeter. As you suspected, it feeds the entire vehicle, passes through the ammeter, then back out to charge the battery.
Leave it alone inside the cab, but you can change it in the engine compartment.

So can I just splice into this large black wire right off the alternator and feed straight to the battery? only downside is no ammeter reading, but I am giving that up anyways. Leave it continuing on to the dash also. Or is it only suppose to be hot when the alternator is running?

You can repurpose the part under the hood, or eliminate it between the alternator and firewall and use a new wire to charge the battery direct from the alternator. That's what everyone needs to do with more powerful alternators anyway.
Is yours still stock? Or an upgrade?

Yeah mine is stock I think... I am assuming that getting a new one with internal regulator may be the best option to cut down on wiring. If I were to get a internally regulated alternator and it just goes straight to the battery can I eliminate the voltage regulator and all associated wires? as long as the large black one still powers under the hood? Or is it best to just keep that intact.

Thank you again so much for your input on this!

 

[Crainbow243]

Ok, while I wasn't seeing the pic during my reply, the "black box" you mention should be the voltage regulator. I thought you might have meant the relay (black) or the fuse holder (also black) but now that I look again, I see your regulator is black also.
So you're mostly good.

Which alternator are you using?
If you have not upgraded to a more powerful and perhaps more modern alternator, I would consider doing so.
The aftermarket EFI setups may not be as sensitive to things as the factory bits are, but I have a feeling they are still going to like a full voltage maintained whenever the engine is running and you don't want the EFI to cough and sputter when you turn the heater and headlights on!

If you have other accessories that draw power, this is even more important.
So if you keep the original style alternator it should be at least 65a rated, and preferably more. Like in the 70-100 amp range.
That's why the modern internally regulated alternators like the 3G are such popular swaps these days. Easy way to get 95 to 130 amps and more of nice steady power.

And you'll be right in there with the new charge wire running directly from the BAT terminal of whatever alternator you use, to the battery side of the starter relay.

And speaking of that, I did not go into detail about that new charge wire before.
As you suggested, running a new charge wire from the BAT terminal to the battery side of the starter relay is a good idea. Makes the run nice and short with fewer potential problems.
But don't undersize the wire either. Even with a small alternator you should be using at least an 8ga wire. If you go with a 3G instead, go to a 6ga battery cable size wire.

This is not because 10ga can't handle it, because it actually can. But the larger wire helps to guarantee a better, more uninterrupted supply to the battery and to the electrical system.
And if you upgrade to a more powerful unit you will already be ready for it if you go with a larger wire now.

Paul

Yeah sorry, those are the fuel pump relay and fuse, both new with the EFI. I did mean the voltage regulator, same questions stands though if it is required with an internally regulated alternator.

I think you may have answered my question about running a wire direct from the alternator the battery, but am I able to eliminate the other one (alt to dash) then?

 

[DirtDonk]

So can I just splice into this large black wire right off the alternator and feed straight to the battery? only downside is no ammeter reading, but I am giving that up anyways.

You won't be splicing into it. You'll be replacing it.
Remove it from the alternator, tape it off for now for safe keeping (more on that later) and replace it with a direct wire from the alternator to the starter relay where it will charge the battery directly, without going through the cabin first.

Your power for the vehicle will now come directly from the battery at all times, and the alternator will simply keep the battery charged.

Yeah mine is stock I think... I am assuming that getting a new one with internal regulator may be the best option to cut down on wiring.

Yes. It gets rid of the whole regulator on the firewall, the Orange wire completely, and you simply run the Green w/red wire (or whatever wire you're using for switched 12v) to the Green w/red wire on the new alternator's connector. And Yellow wire (or whatever wire you're using as the 12v constant) to the Yellow w/white wire on the new alternator.

If I were to get a internally regulated alternator and it just goes straight to the battery can I eliminate the voltage regulator and all associated wires?

Yep.

...as long as the large black one still powers under the hood? Or is it best to just keep that intact.

The Black w/yellow wire will now have a new lease on life, or be killed off under the hood. Remember we're talking about TWO visible Black wires though. They are the same wire of course, just two ends of the same wire.
Let me state this clearly, because it catches a lot of people doing that kind of swap:
THE BLACK WIRE THAT IS CURRENTLY ON THE STARTER RELAY STAYS ON THE STARTER RELAY! LEAVE IT ALONE AND INTACT.
That Black wire will continue to feed the fuse box and all the truck's accessories and running bits.

The Black wire you're changing is the half that is connected to the alternator right now. You have several choices on how to deal with it however.
1. You can leave it at full length, re-route it to the fender, or firewall area and use it to power an accessory power stud, or auxiliary fuse box. This is my preferred method.
2. You can follow it up the line to a convenient spot and just cut it off. Cap it to keep it safe from touching anything, then tape it off into the harness never to be seen again.
3. Or you can simply cut it and cap it off where it is. Tape it up so it stays out of the way, and you're done.
The bottom line is that if you're not going to use it you need to keep it safe from touching metal or other wires. Because it's the other end of the Black wire that is connected to the battery, it's always hot.

A completely new wire will be used to charge the battery. You can make it up yourself or you can buy a pre-made kit. We sell this setup with fuse: https://www.wildhorses4x4.com/product/Battery_Charge_Cable_AMG_fused/Bronco_Starters which you've probably seen me link to several times.
If you're doing super custom stuff, you can make your own but you really do want to protect the circuit somehow. Fuse, fusible link, or circuit-breaker will do the job.
That's all for a larger internally regulated alternator.

If you keep your existing alternator at least for awhile, you can re-purpose the existing Black wire by following it up into the harness and cutting it off with enough left to crimp a new eyelet on the freshly cut end and attach it to the starter relay.
Again, where it's cut off on the body side, you will need to cap it off safely.

Some methods of "capping off safely" would include using an insulated crimp barrel and then covering it with heat shrink tubing. Or just use the heat shrink. Or whatever method you can think of that would keep it safe from short-circuiting.

Paul

 

[DirtDonk]

I think you may have answered my question about running a wire direct from the alternator the battery, but am I able to eliminate the other one (alt to dash) then?

See my most recent post with a description that hopefully gets you there. If not we can cover any individual points that might need clarification.

Basically just remember that you can't separate the connector there behind the ammeter in your earlier pic. That's where the two halves of the wire come together (remember it's one long wire) and if you separate it you will cut off power from the battery side to the fuse box and ignition and everything else.

But basically yes, you can eliminate at least most of the wire under the hood if you don't think you'll ever need to power any additional accessories from it.

Paul

 

[DirtDonk]

I may be wrong, so someone please correct me, but I believe that one of the other reasons for internally regulated alternators, is noise. Or RFI (radio frequency interference) in other words.

External components, especially the old style with mechanical points rather than integrated-circuits. Maybe since the introduction of IC type regulators it's not such a big deal, but you might have read here where ignition components and other things are interfering with the computers for the EFI setups and causing trouble.

So that might be one of the reasons the OE's got away from the old style completely. Then again, fewer wires and external components probably saved them a crap-ton of money too over time.
So I don't really know if that was an issue and should be used for making a decision on which way to go, or not.

Paul

 

[Crainbow243]

Any suggestions for internal regulated alternators for my bronco?

 

[DirtDonk]

Are you keeping the existing engine and from accessory drive?
For most setups, a typical Ford 3G (third generation) is a good add. The Taurus and Mustang (before '96) are good donor vehicles. There's a full list of potential donor vehicles hereabouts, but I have not seen it lately.

Two physical sizes and either one can work in a Bronco. Two ratings are available as well, from 95a peak output, to the more powerful one at 130a peak.
These connect almost like your original, with the Green w/red wire and the Yellow w/white wire.

If you just want simplicity over all, then we have the "1-wire" version of the 3G (https://www.wildhorses4x4.com/product/Hi-Output_Alternator_130-Amp/Bronco_Starters) which is self-exciting so does not need the Green w/red to turn it on with the key. And just leave the Yellow wire that comes with it connected to the BAT terminal along with the new cable to the starter relay.

I prefer the regular type because they're on with the key. But then I don't mind wiring either, so it's fun to do it.
The 1-wire style needs the engine revved up to about 1500 rpm initially after starting, which kicks it on. It stays working at any rpm after that until you turn the engine off.

The 1-wire is going to be your simplest, but a regular will work very well too.

Paul

 

[DirtDonk]

I forgot to mention that it obviously comes with a serpentine pulley as shown in the pic. But your existing pulley will swap over directly, including any spacers that are present.
With a 3G though I do recommend the larger diameter pulleys, or going with a dual groove.

Or convert to a serpentine setup and forget about all the v-belt hassles.

Paul

 

[Crainbow243]

Running into another issue, it won't crank on "start", tracing the wires I have two signal wires going into the starter solenoid. One Red/blue and one brown. I am pretty sure the red/blue is the signal from the start position, but what does the brown wire do? According to the wire diagram it's only on '75s and it goes to a breakerless ignition system, which in sure I eliminated...

 

[Crainbow243]

Found the connector... It ends in a connector that goes to this... Doesn't go through to that metal square.

 

[Crainbow243]

Side note... Red/blue is hot (12v+) with ignition switch in "on" and "start" and the brown has no power or ground in either position.

 

[DirtDonk]

I am pretty sure the red/blue is the signal from the start position, but what does the brown wire do? According to the wire diagram it's only on '75s and it goes to a breakerless ignition system, which in sure I eliminated...

Correct. The Red w/blue wire is indeed your CRANK wire. Should be on the small post usually marked with an "S" and have voltage in START ONLY. Never in the ON position as you note later. However that's another issue which we'll get to.

The Brown wire is on the "I" post and is only hot in RUN. But it's function is related to the starter relay when it's energized in the START mode.
When the starter relay is energized and the starter motor is cranking, there is 12v being passed through the inner relay circuits to this post, and then out to the ignition coil's positive side.
Every Ford from some unknown time in the past, to about the time EFI started to be on all the vehicles had this Brown wire, so it's not a '75-only thing.

If you pull the wire off of the terminal the starter will still turn the engine over and the engine will still run. For testing purposes when you pull the Brown wire off the terminal, with the key OFF you will see 0v on the terminal and 0v on the Brown wire.
With the key ON you will still get 0v on the terminal but now you will see from 8 to 12 volts on the Brown wire because it's connected to the ignition coil's Red w/green wire. They are spliced together at the firewall connector in the stock harness.
With the key in START you will see notably less voltage on the Brown wire (due to the load the starter is placing on the system) and will now see 10-ish to 12-ish volts on the S post.
This is when everything is working as expected...

Found the connector... It ends in a connector that goes to this... Doesn't go through to that metal square.

By metal square, do you mean the ignition control module on the wheel well, with the brand name "Standard" cast into it?

Side note... Red/blue is hot (12v+) with ignition switch in "on" and "start" and the brown has no power or ground in either position.

Two issues here.
1. The wire should never have power with the key in the ON position. So either you have a fault with the ignition switch or there is a short with another wire somewhere. Need to do some testing and detecting then it sounds like.
2 Because the wire is hot with 12v with the key ON, your starter should have immediately started cranking.
Was the wire connected to the "S" post of the relay, or were you still just testing?

Paul

 

[Crainbow243]

By metal square, do you mean the ignition control module on the wheel well, with the brand name "Standard" cast into it?

Two issues here.
1. The wire should never have power with the key in the ON position. So either you have a fault with the ignition switch or there is a short with another wire somewhere. Need to do some testing and detecting then it sounds like.
2 Because the wire is hot with 12v with the key ON, your starter should have immediately started cranking.
Was the wire connected to the "S" post of the relay, or were you still just testing?

Paul

Yes, That is what I meant.

Ok, So looks like the brown wire is not an issue and I have to trace the wiring on the red/blue to see why it is getting power in the "on" position and not just the "start" position.

It originally was cranking in the "on" position, which is why I started troubleshooting and pulled them (brown and red/blue) off to test for the presence of voltage or ground.

Its hard to tell on my wiring diagram, but does the red/blue intercept anything else besides the ignition switch that I should be checking?

 

[DirtDonk]

Yes, but usually the problem is it goes dead and you can't start the engine. Having it short to something with power is unusual.

On any '73 through '77 EB the Red w/blue wire comes from the ignition switch, through the firewall and to a square black 4-wire plug where it either splits off to the Neutral Safety Switch (with an automatic trans) and then on to the starter relay.
On manual trans Broncos it gets a jumper wire instead (looped between two contacts right there at the connector) and then runs to the starter relay.

If yours was an automatic then you could bypass the NSS to see if that's the issue. Since yours is a manual trans (correct?) then somewhere between the ignition switch and the starter relay it's either touching another wire that has 12v with the key on, or the switch is bad.

You can test the switch, and even just disconnect it and test the connector to see if all the other functions work as expected.

Paul

 

[Crainbow243]

Yes, but usually the problem is it goes dead and you can't start the engine. Having it short to something with power is unusual.

On any '73 through '77 EB the Red w/blue wire comes from the ignition switch, through the firewall and to a square black 4-wire plug where it either splits off to the Neutral Safety Switch (with an automatic trans) and then on to the starter relay.
On manual trans Broncos it gets a jumper wire instead (looped between two contacts right there at the connector) and then runs to the starter relay.

If yours was an automatic then you could bypass the NSS to see if that's the issue. Since yours is a manual trans (correct?) then somewhere between the ignition switch and the starter relay it's either touching another wire that has 12v with the key on, or the switch is bad.

You can test the switch, and even just disconnect it and test the connector to see if all the other functions work as expected.

Paul

Yeah I found that connection through the firewall (looped instead of NSS as mine is manual) and it was originally not hooked up (removed with the rest of the coil/ignition wires), but i did hook it back up. Ill spend some time tracing that wire and inspecting the ignition switch, only issues is like I mentioned before, every wire out of my ignition switch is orange... due to the previous owners wiring job, but I have not switched any of them... Worth inspecting though.

 

[DirtDonk]

If you messed with the jumper loop, double check that you did not connect it to one of the Red w/black wires.
It should jump between one Red w/blue wire and the other Red w/blue wire. If you connect it to the wrong Black w/red wire, you'll have power any time you turn the key ON because that's the power wire for the backup lamps.

Paul

 

[DirtDonk]

And for checking the custom color coordinated Orange wires from the switch, get out your ohm-meter and check each one for function.
There are actually charts around hereabouts to show just which contact does which, but I don't have it handy.

One is 12v constant IN to the switch.
One is switched 12v in both ACC and ON. This one is the center stud.
One is 12v switched in ON and START only. This is the one for the ignition and the voltage regulator.
One is for 12v in START only.
One final one that is not part of the main connector is on the outside of the switch and is the Prove-Out or Proof-Out contact for the Brake Warning Lamp on the dash.

Up to you to see which Orange wire is which.

Paul

 

[DirtDonk]

Here's the stock connector and "pigtail" setup.



The center hole is where the ACC stud & wire go.
The wire(s) with the visible connector on the end is the ignition wire. Some pigtails have two wires, some have one. Either way it's the ignition AND voltage regulator.
Yellow is power in.
The other Red wire is the START wire.

This should give you a rough idea of which terminal on the back of the switch does which duty.

Paul

(edited for some more detail on the ACC stud and voltage regulator wire)