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Discussion Starter · #1 ·
I replaced the old alternator that had a single wire connect to the wire terminal. The new alternator has duel connectors. Q. Which of the two connectors would I connect the single wire to. Thanks for the help here guys.

Robert
 

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Are you talking about the plug in with two wires? Or two actual 12V+ lugs on the back of it?
Here is some info on a GM style.



1.This is the main power wire that goes directly to the battery. Make sure it is a heavy gauge since it has to carry the full output of the alternator (up to 150 amps).


2.The left most of the two spade connectors around the perimeter of the alternator (will sometimes be marked "1").

This is the field wire that energizes the alternator; without it, the alternator won't start charging. It must be switched, or else it will drain the battery overnight. Do not wire this into the coil power wire that you use to switch the engine on and off (a seemingly elegant solution, since it would save a switch), since once the engine is running the alternator will feed power back through this wire, which will then power the coil, and you won't be able to shut your car off.

If you wire a lightbulb into this line, it will serve as an 'idiot light' that you can put on your dash.

3.This is the lead for the sensing wire that helps regulate the output. For most hot rod purposes it isn't needed so it can be either left off or jumped over to the main power wire.


4.This is the regulator bypass hole. Sticking a long thin metal object about 2 inches deep into this D-shaped hole causes the alternator to go to full charge. If you do this while it's dark out and the main power wire is disconnected, the whole alternator will emit a cool X-Files type glow. I don't recommend that you try this since you'll likely end up toasting your alternator.
 
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Just info for you.

The alternator pictured above has two different connection methods, one is the 3 wire, the other is a single wire.

The 3 wire is what most of us are familiar with, used on a lot of factory GM and other vehicles for decades.

All I have ever had to do to make one of these a "single wire" use alternator was to do what GM did, run a jumper wire from the BATT lug, #1 in the picture, to the #3 flat blade terminal, and the large cable from the BATT lug to the positive post of the starter/battery. If I wanted to use the charge light, I connected it to the #2 terminal in the picture, and all worked as it was supposed to. If I did not want to run the charge light, the #2 terminal in the picture was left unconnected.

The other way these alternators were set up was for use in industrial and farm use, with a different internal regulator that did the jumper wire for the 3 wire between BATT and #3 terminal inside the alternator. This is the type of regulator and its connect up inside the alternator, that all aftermarket "single wire" alternators of that type use today. The industrial and farm implement regulators are still available today, if one doesn't want to make a simple jumper wirte from BATT to #3 on the outside of the 3 wire alternator.

I have more than 250 persons that have used that 3 wire alternator, with the jumper to single wire, in all sorts of vehicles, including my neighbor's Ford Courier. He is a die hard Ford person, cannot stand anything GM, except the 3 wire GM alternators. We just get a wrecking yard 3 wire unit, clean it up, build the jumper wire, hang it in place, belt it up, and charge away.

Just FYI.
 

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Discussion Starter · #4 ·
Yes I have two terminals on top with the hot wire connected on the back side of the alternator. Of the two slots on top which one does the single wire connect to. Don't want to blow the digital dash out or burn up the wiring harness. Also of the two connectors on the top side, what are their functions, Hot and Ground. Thanks for all the help here guys. This is the last phase of the rebuild before the big Golden Classic's Rally June 1, in Golden Co.

Robert
 

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1957 Chevy Bel Air Convertible; ZZ4 w HEI ign; 700r4; 9" rear w/3:50 gears; pwr disc fr w drum rear
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Robert, I think no one is answering because they are confused by your questions.

If you had a "one wire" alternator before, the "one wire" needs to be connected to the #1 terminal on back side of alternator, as in the picture above provided by MoeDog07.

If you read the posts in this thread, you'll know what the other 2 terminals were for......nothing about hot and ground.

Ace
 

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Yes I have two terminals on top with the hot wire connected on the back side of the alternator. Of the two slots on top which one does the single wire connect to. Don't want to blow the digital dash out or burn up the wiring harness. Also of the two connectors on the top side, what are their functions, Hot and Ground. Thanks for all the help here guys. This is the last phase of the rebuild before the big Golden Classic's Rally June 1, in Golden Co.

Robert
Your answer lies within post #2
He shows all connection points and where they go. Thanks to Moedog07 for posting this as i will be using this info myself
 

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Trifive Automotive Electrical Wiring Expert
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Although the explanation fits the picture posted, it could be a little confuseing. The #2 terminal in the posted picture is actually the #1 terminal of the alternator as molded on most alternators and the #3 terminal is embosed as #2 terminal. If someone tells you the idiot light goes on #1 terminal, it's the embossed terminal, not the output post. You can see the numbers next to the terminals in this picture.

 
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This is so simple, it isn't even funny.

IF the alternator is a single wire from some source, the ONLY connection needed to make it charge is the large BATT to positive on the battery, by direct cable, or through the positive post on the solenoid, whatever, done, charges.

IF the alternator is a 3 wire stock GM type, then, the ONLY connects needed are the BATT terminal to battery positive, by whatever method, AND a jumper wire between the BATT terminal and the number 2 terminal on the side of the alternator (this is NOT the number 2 terminal noted above, but the number 2 terminal as marked on the ALTERNATOR itself). NOTE: THIS IS THE WAY GM DOES IT FOR THE 3 WIRE ALTERNATORS.

With either connect above, if a charge light is used, connect it to the ALTERNATOR side terminal marked "1", done, light works. The charge light does NOT have to be in place for the alternator to charge, nor does the number 1 terminal need to be connected to any source (no charge light, leave it unconnected).

It is as simple as that.

Please bear with me, this is the first time I have attached pictures, to add the jumper wire, and basic GM wiring info, hope it works.

12SI Jumper wire.jpg

Delco 12SI Wiring.jpg
 

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Discussion Starter · #10 ·
Thanks guys, you have made a very clear point as for what wire goes were. Some times my lack of putting the words to make since is a little bit to be desired. I truly understand the wire arrangement now. Thanks

Robert
 
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Don't feel alone, I have to edit my own posts and stuff a few times, in hopes others might understand what I am saying. I get it, but don't convey it well most of the time.

I am glad to see my attachments came out well, first time I ever attached anything to a post, anywhere. All I have to do now is figure out how to make 'em bigger. Great that they are changeable size wise, though.

If you have 'em, keep those questions coming, we'll keep the 'confusing answers' coming (hahahaha), that is what this sport/hobby is all about.
 

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All I have to do now is figure out how to make 'em bigger. Great that they are changeable size wise, though.
Lil' help from your friends @ bowtie-trifive

 

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Got your PM, thanks. Using Mozilla Firefox.

I had an idea that the attachment menu had changeable pixel sizes, but, just tried to change the numbers,but, they aren't adjustable.

Drat, it's never easy.
 

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Got your PM, thanks. Using Mozilla Firefox.

I had an idea that the attachment menu had changeable pixel sizes, but, just tried to change the numbers,but, they aren't adjustable.

Drat, it's never easy.
Dave....I have Mozilla Firefox on my computer at home.....When I get there, I'll see how its done using that browser and let you know.
 
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