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3G Alt on a Classic, wiring?

tarafied1

tarafied1

Well-Known Member
My 40A or 65A original replacement alt is giving up on me. It's only about 4 years old but anyway, I figured now with a kicker stereo I should consider a bigger Alt anyway. I have a 3G 130A from a 94 Cobra with the wiring harness. Basically three small wires and a big one. Looks like I can make the Alt mount okay and I think I can swap the pulley. Just need advice on how to wire it up and eliminate the old VC and wires. This should clean up engine compartment too.
 
PA Performance sells a kit that will replace the existing regulator and all the other bits to wire it in. I was rewiring, so I did the conversion myself, but I did buy the 3G plug from them. Great product & service.
 
my 3G alt has the wiring harness/plug on it. How hard is it to just do myself?
I found this for a 95A 3G...
 

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thanks, that should be easy enough. The only thing I'm not clear on is the one that goes to the ignition switch. What does it do?
 
I'm pretty sure thats the same Lt Green/Red that is at your regulator now, I think you can cut it there and continue it right to the 3G alt.
 
The only difference for me was the stator wire hookup. The shop that I got the alt and harness said that the stator was optional and not to bother hooking it up. I've been running that way for over a year and nothing has exploded on me.
 
I currently have my electric choke hooked up to the stator on my wimpy ALT. Nothing was hooked up to it before. Can I still hook up my choke on the 130A 3G?
 
Mine is hooked to the stator now, no problem at all.

Check the wiring diagram -I think the grn/red wire goes through the old regulator, and may not give you what you need. Don't have them available now, Mid may be more help here-
 
OK, my memory is correct (at least for the 68, and I think the 67 is the same). The stator wire at the existing alt does not get 12V power all the time- it is switched on & off by the regulator. To use that wire as your 12V 'on' wire, you will need to jump wire 35 and wire 904 at the regulator (and remove them from the regulator). That is what I did, and removed the regulator completely - if you do this, wire 152 can be cut and terminated. My headlight relays now use that real estate.

275-181011054943.jpeg
 
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okay, I'm still confused. I get that I can hook (jump) 35 and 904 together. My regulator is wired as in the 68 diagram. There is no wire on the "I" terminal of the regulator. SO if I follow the above diagram for the 3G, where does the LG/Red wire go?
I have the harness from the doner 94 Cobra...
 

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Edit: I just realized you are saying there is no green wire on the I terminal of the 3G. That being the case, I'm lost - I thought they all had that to activate the regulator. So, if it had the wire, the description below would work:

There are 3 wires coming from the plug on the regulator - one goes to the stator (on the alt), a yello one goes to the voltage sensing point, and a green on goes to the lg/red wire (wire 35). Hard to see in your pic, but it looks like that wire is the one with the bullet connector. The yellow goes to whereever you want the regulator to control your voltage - if you are using a 6 ga cable for the alt output, wiring it to the output post of the alternator worlks fine.
 
no I confused you now. I do have the green/red wire on the 3G, I don't on the 67 Mustang. #35 looks like it might be green/red but it was not hooked to the "I" terminal on the external regulator on the car.
Are you saying I can hook the green/red wire from the 3G to the #35 on the original harness? And I can hook the yellow wire to the charge post on the back of the Alt like this?
3Galternator16.jpg
 
Yes, that's how I did it. The I terminal on the 3G (I think always grn/red, but hey, it's a Ford) should be hooked to the 35 wire from the old alt, and that should be jumped to the 904 wire at the regulator. Wire 35 will not be hooked to the I terminal on the external regulator - you are using it for a different function (extending the I wire, or wire 904). You can test to see if you have it correct before hooking to the 3G - the 35 wire, when jumped correctly to the 904, should have battery voltage on it when the ignition key is in "run", but no voltage when it is in "off".

The A terminal on the 3G (yellow) should be hooked to the charging post. It senses the voltage put out by the 3G and raises / lowers it approriately. Just for information: the A terminal can be hooked to other points (I hooked mine to a new fuse block I added under the hood) if you want the voltage to be held constant at that point. But, for 90% of people, just hooking it to the charge post works great.
 
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