4G wiring for dummies, like me:)

[73azbronco]

Just to clarify, this is the 4G alternator found on the Ford Explorer serp setup.

Strangely could find no thread specifically on the 4G, many 3G. I had to dig into some of the great RJM tech schematics which I'm not going to bore you with.

OK maybe just one. But it is copyrighted so I'm just supplying the link to his pic.

http://www.grandmarq.net/oldfuelinjection/public/alternator/4G-ALT_wiring.gif

Who uses an alternator idiot light? Nobody right? So to keep it simple:

Hot battery cable type wire off M6-1.0 threaded post to fuseable link to battery plus side. Yes, a metric threaded post on a Bronco. I sourced these wires from WH, comes with fusible link of ginormous proportions. I also sourced some battery/alt/starter cables for F250-350 for later use but not going there this year.

Next, the three control wires out of the s-545 connector on the alternator.

Since I keep it simple, using the RJM diagram the green wire with in my case a red stripe goes to run/hot on the starter solenoid. 20amp inline fuse or fuseable link wire would work. 20A seems excessive, but what do I know.

The next wire is the yellow wire with a white stripe. That jumps over to the M6-10 hot output post.

The last wire which in my case is a white wire with a black stripe, is not used. Seal it as required.

I sourced three junkyard connectors and all of them were flimsy heat damaged. I bought the new connector from summit for $10. https://www.summitracing.com/parts/smp-s545

Done.

 

[76 bronco J]

>>> 3G & 4G alternators wire mostly the same & use the same plug.... the only difference is the white/black striped wire isn't used on the 4G..... the reason is >> the stator or "S" terminal wire which enables the voltage regulator to detect that the alternator is operating has been removed from the harness it is now connected directly to the rectifier assembly through a regulator mounting screw.....

 

[Viperwolf1]

Since I keep it simple, using the RJM diagram the green wire with in my case a red stripe goes to run/hot on the starter solenoid. 20amp inline fuse or fuseable link wire would work. 20A seems excessive, but what do I know.

Looks good except for this. Instead of using starter solenoid wire use the green-red wire from the old 1G voltage regulator. It keeps you from stealing current from the ignition system. 20 amps does sound excessive. I would be surprised if it pulled more than 2 amps. All it does is turn on the regulator.

 

[73azbronco]

I'm starting from scratch so no wiring left Going painless, or so they claim.

I'm betting that's a typo, it can't be more than 2amps on the run position green wire. Unless it's going into a switched section after a relay for use to power all the "run/on" stuff like radios/etc.

 

[DirtDonk]

I had to dig into some of the great RJM tech schematics which I'm not going to bore you with.

Just to be clear, does this mean you're using an RJM EFI harness? Or just using them for information purposes?

Who uses an alternator idiot light? Nobody right?

Correct. Nobody, or almost nobody bothers with hooking one up. But I'd like to do that on my next one anyway. Seems like a good backup to a gauge.

Hot battery cable type wire off M6-1.0 threaded post to fusible link to battery plus side.

Yep.

I sourced these wires from WH, comes with fusible link of ginormous proportions.

Thanks. Should be our #6025 then? It's just a fuse then. Not actually a fusible link. Really a 175amp "Mega-Fuse", and yes it's a big'un.

...using the RJM diagram the green wire with in my case a red stripe goes to run/hot on the starter solenoid.

As Viper said, not the best place to run the wire from.
If an actual RJM harness there is already a wire built in for this purpose. Guessing you're not running Ford EFI with this setup then, so finding the old original Green w/red wire would be your best bet.
If it's cut off you can find it at the back of the ignition switch and catch it there.

20amp inline fuse or fuseable link wire would work. 20A seems excessive, but what do I know.

Not just excessive, but I've never seen any diagram showing this circuit with a fuse or link at all. No protective device between the ignition switch and the regulator that I've seen. Probably modern cars run it through the fuse panel and probably control it from the computer. But not ours.
Keep it simple...

The next wire is the yellow wire with a white stripe. That jumps over to the M6-10 hot output post.

Yep.

The last wire which in my case is a white wire with a black stripe, is not used. Seal it as required.

Yep again.
But don't cut it off just yet. If you ever have to run a 3G it would come in handy. The plugs are the same. Just the number of wires used varies.

I sourced three junkyard connectors and all of them were flimsy heat damaged. I bought the new connector from summit for $10.

Looks like a good idea.

Good luck.

Paul

 

[Rustytruck]

I used the red and green off the throttle position solenoid wire on my 1974 its only live when the key is on. Since swapping to my Quadrajet it doesn't use this solenoid connection and its right on top of the motor. In your case with a new wiring kit you can establish a new key on power of your choice. BC Broncos has a good 3G wiring chart on their web site.

The 3 g alternator needs a good case ground so make sure you have good clean ground path through its mounts or run a good heavy ground wire from the case to ground as I did. There are threaded case holes making it easy to do.

 

[73azbronco]

Dirt donk spot on buddy. Sourced wire is the WH part, yeah, not fusible but the 175 amp fuse. I am NOT going EFI so the green wire will go to the run post on the starter solenoid with no fuse. Maybe I'll throw a fuseable link section in. And by cut off the white wire, Ill end it with sealant and wrap it inside the harness I'm building. All good points.

I plane to run a battery cable from one of the case mount bolts which attach into the explorer serp bracket, down to my main ground strap on the engine block.
Figure that will last about 1000 years of good grounding. That serp bracket has been painted and powder coated to many times over the last 10 years during this build so not to sure it can even provide a ground path


I just thought it odd no one ever showed a 4G thread, now we have one that says, pretty much like a 3G

As an aside I'm having issue withthe starter solenoid choice. One I thought would work woun't let the WH manly man battery cable properly seat, the cables are to big. So I'm ordering a ford solenoid which should work part number:

https://www.amazon.com/gp/product/B000C5FTKY/ref=oh_aui_detailpage_o02_s01?ie=UTF8&psc=1

 

[73azbronco]

OK, starter solenoid shown above was a failure. Looks great, very heavy duty but showed up missing parts and looked like it had been used. So I'm staying old school solenoid for now.

 

[DirtDonk]

...very heavy duty but showed up missing parts and looked like it had been used.

Now that's funny right there. Except for the hassle part that is.
But to think of one of these simple things actually missing parts is a sad thing to contemplate.

What was missing? Just the two nuts hopefully?
Maybe they expected you to use your old ones that you don't have? Someone else either borrowed them, or returned it to the supplier for the same reason you are going to!

Anyway, old-school still works.

Paul

 

[DirtDonk]

I am NOT going EFI so the green wire will go to the run post on the starter solenoid with no fuse.

As long as there is still the other wire from the ignition then you should be good. Remember there is no power at that post otherwise, except during START only.
You mention a white wire. Is this a Centech harness?
I know I should know your build by heart by now, but humor me!
If so, leave it in place or the Green wire won't get power under normal RUN conditions and you'll be chasing your tail looking for more power, just like Tim Allen.

As an aside I'm having issue with the starter solenoid choice. One I thought would work wouldn't let the WH manly man battery cable properly seat, the cables are to big.

Interesting. I wonder if our supplier (or we) changed the ends. Got a pic of how they fit? Or didn't fit that is?

Thanks

Paul

 

[76 bronco J]

Interesting. I wonder if our supplier (or we) changed the ends. Got a pic of how they fit? Or didn't fit that is?



Paul

>>> think what he's talkin' about is the 2 little nubs on each side of the 4G main terminal that prevent a full size lug from sitting flush.... pic below points to what's left of one that I snipped off to let the 4 gauge cable lug sit flush....

 

[73azbronco]

To pic above on alternator lug, yes the wild H smaller wire fits a stock 4G. This is the wires which are on the 150- amp mega fuse from WH. However, the gynormous lugs on the fullsize battery leads/cables from WH (which I like BTW) and starter leads need either a stock relay or a heavy duty relay for the end lug to fit over the screw and fit on the post.

The heavy duty ford relay noted a few posts above I sent back, looked like it had been used so it was a non user IMO, yes, missing parts and instructions were for different 4th world relay making me think this was also a black market knockoff, just didnt look right..

The white wire I describe is the middle sense wire on the 3 wire control plug for the 4G. I just sealed it off and will wrap it inside the bundle. I think it has to do with EFI control and or monitoring control of voltage in the PCM or EFI box..

Yes, since my wiring is virgin, I may just route the green sense wire to the MSD ON position and bypass the relay all together except for start wire.

 

[bronco italiano]

>>> think what he's talkin' about is the 2 little nubs on each side of the 4G main terminal that prevent a full size lug from sitting flush.... pic below points to what's left of one that I snipped off to let the 4 gauge cable lug sit flush....

On the 4G can I just run the ylw wire from alternator (A) to the charge lug since it is constant 12v?

 

[BruiserOutdoors]

I followed what 73azbronco suggests but I dont know what to do with the factory wiring. Specifically the old alternator wiring and voltage regulator. Suggestions?

 

[DirtDonk]

What do you want to do with it?
And which ones? All of them?

First, you no longer need the old voltage regulator, so remove it if you have not already.
The 3 wires and their plug to the regulator can go bye-bye as well, but it's standard operating procedure to keep the old Green w/red wire and the old Yellow wires handy for any future need of a constant, and a switched power source for some accessory or another you might install later. You can keep them in the plastic connector to protect the ends from shorting out, or you can cut them off and cap them safely and tuck them out of the way.
But you can also use them in their original functions, by connecting them to the new alternator. More on that in a bit.

The original Orange wire between the regulator and the alternator gets tossed out.
The original Black w/yellow wire from the back of the alternator MUST be protected or removed. But not entirely removed. Just cut down to the point it's not hanging out there.
But most of us retain it for use with heavier accessory loads. Such as by mounting it to a terminal strip, or terminal block, to use as a power source for multiple items. It's a heavy (10ga?) wire with a direct (though circuitous) connection to the battery. So cap it, or terminate it on a power strip.
The opposite end of that wire is a Black wire at the battery side of the starter relay. You MUST keep this in place, because it is now the defacto power source for your entire Bronco universe. If you remove that one, like many do, thinking it's just part of the charging system, then you will have no power to anything, anywhere, any time. So keep it intact.

If you have a standard 4g alternator, your old Red w/green wire we talked about from your old regulator, to the Red w/green wire in the new alternator/regulator plug.
If you have a standard 4G alternator, your old Yellow wire can be connected to the new Yellow w/white wire in the new alternator/regulator plug.
Most just follow the more popular instructions (because it's easier) and connect the new Yellow wire to the BAT terminal on the alternator. I prefer to connect it to the old Yellow wire, so it senses the battery voltage up close and personal to the actual battery.
And you have to get your switched power source from somewhere, so it might as well be the old Green w/red wire. It is already connected to the ignition switch, and is already the correct color code for the alternator/regulator. Making it a natural.

Paul