3G alternator question

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Ken Dixon

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I'm new here and would like to say hi, I have a 1974 Bronco that I have been working on for a couple years.

I recently installed a 3G alternator which was configured for just one wire hookup. Well all went ok and it works and charges as it should. The problem is I thought I shouldn't need the old regulator so I took it and the associated wires out, then I had no electric anything. So I looked and the problem was a small black wire which has a fuseable link then it splits into a large black wire which runs to a connector and a small yellow wire which goes to the old regulator. What do I need to do to clean up my wiring and remove the old regulator?

Thanks Ken

 

Seabronc

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A picture if the wiring would be great.   You were right, you do not need the old regulator, it is on the alternator.  any wores that went to the old regulator are no longer needed and you can eliminate it.  The black one sound like it goes to wherever power is distributed, it probably use to connect through the fuseable link to the starter solenoid, (battery side).  If that is where the end of the fuseable link goes and it is bad, you need to replace the link or install a fuse in it's place.  The fuseable link is there to prevent overloads that could cause an electrical fire, unfortunately they have been known to burn up and cause an electrical fire.  Have you added to the electrical load?  Did you install a Mega fuse?

Basically the old wire ti the battery is removed and replaced with a #2 cable to a Mega fuse then from the fuse one #2 to the battery and a #2 to the starter solinoid, if there is a power distribution fusebox under the hood there would also be a #2 going to it.

Attached is a typical installation diagram and a picture of a typical installation.

Alternator hookup copy.jpg

 
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Ken Dixon

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This picture is taken towards the firewall, you can see the yellow wire which goes to the regulator and the heavy black one which goes to the connector plug. They both split off from the fuseable link which attaches to the start solenoid.

Do you mean I should be able to just cut off the small yellow one running to the solenoid and cap it?

The alt I got was from quality power it's 100 amp they said just run a #6 wire from it to the solenoid.

Ken

image.jpg

 

Seabronc

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This picture is taken towards the firewall, you can see the yellow wire which goes to the regulator and the heavy black one which goes to the connector plug. They both split off from the fuseable link which attaches to the start solenoid.

Do you mean I should be able to just cut off the small yellow one running to the solenoid and cap it?

The alt I got was from quality power it's 100 amp they said just run a #6 wire from it to the solenoid.

Ken
First off,  a number 6 wire is a little light, I wouldn't do any less than a number 4 with a 100 amp alternaator.  A number 6 will work but only because you are not drawing the full load of the alternator.  If you add more load like Off Road lights, sound system, etc. a number 6 wire will start to get hot and cause a voltage drop in the systemthat you don't need.  If you had put in a 130 amp alternator then # 2 is best.  In other words, 6 will work but 4 is electrically better.

With your alternator, (just as in the above diagram), I recommend a #4 from the alternator charge terminalto a 125 amp Mega fuse.  From the fuse to the battery #4, from the fuse to the battery a #4, from the battery to the start solenoid, whatever was originally there (standard battery cable). 

That gets the start and charge system functioning properly and safely.  The next thing is to reestablish connection to the rest of your electrical system.  A secondary objective is to get rid of the old voltage regulator and wires thar originlly went to the old alternator/generator.

If you had an Ampmeter on the dash, it will no longer function.  From my experience, most of them didn't work any way so no big loss, a voltage meter is a better indication of what's going on with your alternator anyway.

I'm adding a picture of the 3G alternator harness that I expect you are using with some comments on the picture. 

3G-ALT_wiring 1.jpg

The yellow wire is the voltage sense wire, It lets the alternator know what to do in regulating the voltage output.  If it is connected to the point of distribution for the electrical system it will do a better job of controling the voltage output level.  Though connecting it at the charge post lets the regulator know  what level the alternator is putting out, it is more accurate if connected further down the line, (if you dont understand that, I don't want to waste time inputting the defense of that statement in this post, just believe me, it is true). 

The white one obviously goes to the alternator field connector.  

The Green with red stripe connects to the green with red stripe wire in your old connector from the dash.  It should be one of the wires going to the connector thar is unplugged.  Cut it and connect it to the green with red stripe wire going to the alternator harness.

To make the connection to the voltage distribution point I need to see where those two black wires go that are in your picture.  I assume one goes to the fuseable link.

Waiting for your input and perhaps a coupe more pictures. If I were there we would have this done in about 10 minutes.  The extreem tunnel vision I have under your hood makes this a little difficult and I'm not sure if what I have said so far is confusing or makes ant sense to you.

At this point, I would need to see where the black wires in your picture go. 

:)>-

 

Seabronc

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Sorry about the speling in that picture, here is a corrected one.

3G-ALT_harness.jpg

We are going to get rid of that old regulator.

:)>-

 
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Ken Dixon

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These are pictures of the wiring I have. One shows the ends that went to the original alt, one shows the wire with the fuse link that splits into a large black one and a small yellow one. One shows the connector and the regulator.

My new alt has some kind of a plug in harness already on it which makes it so there is only the large output connection to hook up to. I have no harness like you pictured.

So I have hooked to that positive terminal on the alt with a #6 wire which goes to the battery side of the start solenoid. The person at quality power said there was no need for a mega fuse in that wire.

The two wires I am unsure about are the small yellow one which goes from the fuse link to the old regulator and the large black one which went from the original alt to the plug connector by the firewall.

Ken

image.jpg

image.jpg

image.jpg

image.jpg

 
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Ken Dixon

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I tested the new setup and had 14v at the battery so it is charging.

Ken

 

Seabronc

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Granted you can get it hooked up without a megafuse but that leaves your alternator unprotected from overload.  Perhaps you have an alternator that has changed the design?  I don't know.  All I know is that the hook up diagram provided above is the best way to hook it up.  You don't need any of the old wiring except the black one that goes from the fudeable link to the point of distribution.  You can trash the ol voltage reguator, it is incorporated into the 3G. I can install one of these from scratch in 30 minutes that has a clean installation, done it several times.

That harness is the one that has always gone with the 3G unless something has changed, it doesn't come with the alternator.  You either have to go to a junkyard and get one off a 3G there or buy one. Give me a picture of the wiring to the alternator.  Maybe I'll have to adjust my thinking.

:)>-

100_3347a.jpg

 

Seabronc

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Here are a couple more pictures of an installation that would be close to yours.

100_3364a.jpg

100_3365a.jpg

Interm wiring A.jpg

 
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Seabronc

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OK, it has the harness that I showed you a couple of replies above.  It appears to have the 'yellow/white stripe' wire going to the charge terminal, which is correct.  I can't see the other two wires in the plug, but I assume that the 'white/black stripe' wire connects back into the alternator, which is correct. 

What does the third wire, (I expect it to be 'green/red stripe'), in that gray plug connect to?

Back in your post that shows the start solenoid, what do the two black wires that are in the plug next connect to?  I know one goes to the fuseable link, where does the other go?

I'm attaching a wiring diagram that I hope helps, it is for a later model Bronco but the way I suggest that you have yours configured.  Again it shows a fused connection for the alternator output, Ford thinks it is a good idea to have a fuse there and I totally agree with them.  It shows the yellow/white stripe wire at the alternative location I mentioned above, (again, where the 'yellow/white stripe' wire is currently hooked is OK but won't give you the best voltage regulation). 

I think if we resolve the old black wires that are shown in the plug in the previous solenoid picture, we will have you with power to the rest of your electrical system.  You can trash the voltage regulator.

:)>-

Power Modifications 001.jpg

100_3347a.jpg

100_3349.jpg

 
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Ken Dixon

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The one large black wire coming from the plug went to the power out from the old alt. I am thinking to just cut it and cap it and do the same with the small yellow wire that runs from the fuse link to the regulator. I think that should work after studying the situation.

Thanks Ken

 

Seabronc

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Ken,

If you don't have power to the rest of your truck, then something still needs to be done.  Trace the line from the fuseable link, it should have a path to the fuse box.  Without a wiring diagram for your truck, I'm working a little blind but I suspect that one of those black leads needs to be reconnected, probably spliced to the fuseable link.

miesk5, do you have a diagram for this truck?  I thought I had one but can't seem to find it.

:)>-

 
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