3G 3 wire help please

[Timmy390]

Trying to figure out the integration into the Bronco harness. I've already taken off the stock regulator.

My 74 has a plug on the firewall with 3 wires, black, black and green/yellow/red (faded badly)

Guessing the green/yellow/red connects to the green/red from the 3G Alt.

The 2 black wires should be black/yellow and black/red but they're solid black. One is bigger than the other.

The larger black wire comes from the stock Alt (runs to the AMP meter?)
The smaller black wire is hooked to the BAT side of the starter solenoid (powers the fuse panel ?) Neither are fused

How do I hook these wires up? Do I remove the wire coming from the stock alt? Cap it off maybe? Add a fuse to the smaller wire and hook it back up t the BAT side of starter solenoid?

I've read so many posts and looked at so many diagrams my eyes are bleeding. The wiring in my truck SUCKS and is hacked all to hell but it works (on most days).

Tim

 

[pcf_mark]

Ta-Da!

http://www.bcbroncos.com/3ginstall.pdf

All you need to do is check the old wires from the regulator and see what is hot with the key on.

 

[cs_88]

I've seen schematics that show it both ways, some connect the black/red some the black/yellow. Either way connect one of the black wires to the starter solenoid with the charge wire from the alternator and cap the other one off. Both wires loop through the stock ammeter.

 

[DirtDonk]

Yep, what they said.
And it's not uncommon for much of the Black wire length to not have the stripes for some reason. Some years were only Black w/yellow for the alternator and all Black for the battery. Some (later years) had the red stripe, but even then, the stripe was just not on 100% of the wire.

There would have been a fusible link end/section between the starter relay/solenoid and the 3-wire connector. If the ring connector with the molded plastic end is no longer present, then it's possible the PO replaced it with regular wire after a meltdown.
Wouldn't hurt to check of course, as that circuit should be protected after all. If it's just standard wire, a 60 amp Maxi-Fuse would do the trick.
The fact that you say one wire is slightly smaller than the other though, might indicate that the fusible link section is still intact.

Sometimes it's just easier to connect the other Black wire (with the yellow stripe/trace) from the alternator to the same battery side stud on the starter relay as the other Black wire. Remember, positive and positive don't short each other out, so they can both be connected to the same origin even though they're basically a loop, and therefore opposite ends of the same circuit.

If there is enough room on the stud, use it. If not, then you can cap it off securely.

Paul

 

[Timmy390]

Thanks guys. I'm buttoning up the last few things on my 351w/EFI project.

Still have some wiring left (in the process of finishing that) throttle cable (just needs to be trimmed), fuel lines/pump, exhaust and ECU program (dropping it in the mail to EFIGuy today).

Tim

 

[Steve83]

This diagram show the simplest way to do the swap: reuse the original VR wires; abandon 2 factory wires; add 1 new wire & fuse (and delete the original ammeter):