Universal harness with one wire alternator

[Boss Hugg]

I'm using a 21 circuit EZ wiring harness, and it has two wires I think I can use for exciting the alt. one is a big red wire (probably 10ga) marked alt power, the other is a 12ga white wire naked alt exciter. Which one should I use? If I go white, on this somewhat custom rig, I'll only have the solenoid start wire coming out the firewall on the right. The rest are on the other side...

 

[DirtDonk]

First, let's clear one thing up. Is this in fact a true 1-wire alternator? Or is it just a standard "internally regulated" alternator?
They're completely different, and a true 1-wire does not need any excitement from the chassis harness. It get's it's own.

What alt are you looking at by the way?

On the other side of that coin, usually a big Red wire of that gauge is almost always full-time battery power and not acceptable for key-on only work. Besides, that wire is likely expected to be the main charge wire for lower powered alternators anyway.
Anything over 70 amps output should use a dedicated wire of larger gauge. Depending on the length and amperage, anything from 8 gauge to 2 gauge. Ford uses 6ga and 4ga on most of their modern rigs. Every setup is different though, with different needs.

Paul

 

[Boss Hugg]

OK, so its a 2 wire Ford although off a mustang I think. Worked before I started this project with a lawn mower batt cable between although and battery side of solenoid. Green/red wire excitor.

I guess I just need to use the white wire and cap to red wire off under the dash.

Also, can someone post a pic of a true one wire although? I've never seen one.

 

[DirtDonk]

Here's an image of our 3G "1-wire" setup. http://www.wildhorses4x4.com/product/HiOutput_Alternator_130Amp
It doesn't show the business end, but it basically looks like any Ford 3G except for the missing Green w/red wire in the plug.
Some others that are also used are GM conversions. Don't have any pics of that, but I've seen some here over the years.

The way it sounds like yours was connected before should be just fine. Large wire between the main output post on the alternator, directly to the battery side of the starter relay/solenoid.

And the Green w/red from the Bronco wiring, to the Green w/red (sometimes just green) of the alternator.
Mustang's alts of this type would have been either a 2G or a 3G depending on what year it was sourced from. Obvious difference was the 2G had two output wires coming right out of the plug/connector, while the 3G had a single separate stud w/nut to connect the charge wire to.

Should be easy to determine a good exciter wire from the EZ Wire harness. If you're not sure about one or another, just check it with a volt meter to make sure it's only getting power when the key is on.
Are you at that point in the install yet? Or are you still putting things together with the harness and it's not quite ready to run yet?

Paul

 

[Boss Hugg]

I used that alt power wire for a headlight power sourse to my relays controlled by the harness' headlight wires. The white wire will be the excitor wire.

Im almost done with wiring. I've had issues making a front turn signal work right, but a set of "equalizers" resistors fixed it, and the the horn setup with the steering wheel install kit I bought. Ill do a right up on the fix so others might see how to make their horn buttons work right.

I had the dash done last night, almost finished everything under the hood and hope to get the rear done tomorrow night. But I'm hearing hints that I'm loaned out to the wife's chores tomorrow. I use this as a push truck at the local dirt track and they start next Friday! Don't have time for chores...
thanks for your help Paul. Looking forward to my led inst cluster lights I ordered Friday! Wish I could afford those new light bars too but...

 

[DirtDonk]

Yeah, the light bars can come later it sounds like. But boy oh boy, are you going to be stoked at being able to read the gauges, even with the glare of the stadium lights. Heck, you'll see the lights in the daytime with your new harness and the LED's!

Have fun. But hey, doesn't your wife understand about deadlines? ;D