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1970 Bronco Alternator Wiring

dmkcasey

New Member
Joined
Oct 30, 2009
Messages
6
I have just gotten my recently purchased 1970 bronco running after a few years of sitting around in someone's driveway, but I am having electrical problems. The problem appears to be a lack of charging from the alternator. I bench tested the alternator, and it appears to be fine.

The weird part is that the voltage regulator seesm to be mounted to the back of the alternator. The alternator is then wired directly to the starter selonoid hot post with one wire. Does this seem right? I think it is the stock style alternator because I compared it to one at the auto parts store - and it appears identical, except no voltage regulator mounted on the back.
 

70_Steve

Old Guy
Joined
Dec 13, 2002
Messages
8,317
Welcome to the site.

Having the alternator output wired directly to the solenoid BAT+ post is typical of an upgraded alternator. The stock wiring has the output of the alternator going through a "loop" that taked it behind the dash to the ammeter, then back out to the BAT+ side of the solenoid. The 14 ga wire used in that loop is only good for the stock 55-60 amp output.

Some pictures of your alternator would help. Or you can take a look at the FordFuelInjection site. Ryan has pictures of the different alternators Ford used. See if you find one that looks familiar. http://fordfuelinjection.com/?p=63
 
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dmkcasey

New Member
Joined
Oct 30, 2009
Messages
6
Thanks for your help - I have been silently reading post after post on this site - all you guys are son knowledgable and have given me lots of insight transforming my bronco to what it is today.

I am ready to pull my hair out with this charging issue. I definitely have a 1G ford alternator, the first on in the link you sent me, with the regulator mounted to the back of the alternator. there is an "extra" orange wire sticking out the back of the regulator that does not connect to anything?? Does that need to be connected to instruct the alternator to begin to charge? I am trying to figure out how to post a picture - maybe that will help.
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,316
Thanks for your help - I have been silently reading post after post on this site - all you guys are son knowledgable and have given me lots of insight transforming my bronco to what it is today.

I am ready to pull my hair out with this charging issue. I definitely have a 1G ford alternator, the first on in the link you sent me, with the regulator mounted to the back of the alternator. there is an "extra" orange wire sticking out the back of the regulator that does not connect to anything?? Does that need to be connected to instruct the alternator to begin to charge? I am trying to figure out how to post a picture - maybe that will help.

Here are the connections needed to make the 1G work.
 

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70_Steve

Old Guy
Joined
Dec 13, 2002
Messages
8,317
Here's another link to the wiring for the alternator.
http://www.wsu.edu/~i6735189/68-71ign.gif

The alternator only has three connections. The output of the alternator, the Field connection and a ground. The orange wire should connect to the Field. Your 70 should not have a connection to the Stator terminal. That was used to power the electric choke.

To post pics, you either need to upload them to a hosting site, then put a link to the pic in this thread. Or, pony up $12/year and become a Contributor. Then you can post pics right in the thread. See one of the Sticky threads at the top of the Chat section.
 
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dmkcasey

New Member
Joined
Oct 30, 2009
Messages
6
Thanks guys, i will gladly pony up the 12 bucks - the site has saved me 10 times that much already.

The problem I am still having is the voltage regulator is not the stock one mounted on the firewall, it is a small connection on the back of the alternator? Does the wiring diagram still apply?
 

70_Steve

Old Guy
Joined
Dec 13, 2002
Messages
8,317
The problem I am still having is the voltage regulator is not the stock one mounted on the firewall, it is a small connection on the back of the alternator? Does the wiring diagram still apply?
Dunno about the other guys, but it would be tough to say how the regulator gets wired up if we don't know what regulator it is. Are there any numbers on it?
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,346
So you're saying it doesn't even look like a stock one then? Even if it's bolted to the back, it is likely to have the same connections. And the alternator itself will usually have the same posts/wires connected no matter where the regulator is.
Is the regulator plastic? Metal? Smooth? Finned with a round diode sticking out of the middle?

Paul
 
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dmkcasey

New Member
Joined
Oct 30, 2009
Messages
6
Paul - it looks very similar to the stock one, but probably a quarter of the size - the connections are hidden between the alternator and the Voltage regulator, so I will have to take it off to see what the connections are.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,346
Yeah, probably worth the trouble though. If not only to verify what it is, but to check the alternator and it's connections AND the condition of the wires.
I don't suppose there's anything wrong with it being direct-mounted (after all, new ones have the regulator inside the alternator), but it sounds a bit awkward.
Let us know what you find. As mentioned though, the Orange filed wire should be from the "F" terminal on the regulator (if it's marked) to the "F" or "FLD" terminal on the alternator.
That's the wire that lets the regulator tell the alternator how when and how much to charge.

Paul
 
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dmkcasey

New Member
Joined
Oct 30, 2009
Messages
6
Thats what I thought viperwolf - Thanks for all the info - I have read a bunch of posts from you regarding electrical issues. What do you recommend if I step up to a 3g?
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,316
Thats what I thought viperwolf - Thanks for all the info - I have read a bunch of posts from you regarding electrical issues. What do you recommend if I step up to a 3g?

Yes. Get a 3G. You already have the correct wiring going to the old alternator. You'll have to search for the application or maybe someone will chime in with that info. I'm using a 4G.
 
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