Voltage Regulator/ Alternator

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Oct 29, 2012 | 03:20 PM

forddieselnewb

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Joined: Sep 2012

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Voltage Regulator/ Alternator

My alt light shows up and disappears and the gauge goes low to normal periodically. I have had trouble starting it up and need a jump a couple times just hoping it to be a 20 dollar part and not a 100 dollar. How do you test the external regulator? I checked mine today and there was some corrosion present so I cleaned them up a bit. there has to be a way using a meter but i just do not know it. 90 f250 non ambulance 7.3 diesel e4od trans

Cheers folks

Oct 29, 2012 | 03:37 PM

Onus

Fleet Mechanic

Joined: Jun 2009

Posts: 1,320

Likes: 1

From: CT

Check your belt, batteries, voltage regulator. Very rarely does the alternator go bad. I forgot the exact steps to check the voltage regulator. But, if you search on how to see if 1g ford alternator regulator is bad. You may be better off replacing it they are only $20.

I think the check for the regulator is check with a multimeter when the truck is running what voltage is going into the batteries. It should be around 14.5. If not replace the regulator.

My light comes on when my batteries need to be charged up so check those too.

Oct 29, 2012 | 04:02 PM

hairyboxnoogle

Lead Driver

Joined: Apr 2008

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The 3G upgrade cost me $26 at the local pick'n'pull for everything i needed, not to mention a pocket full of fuses, bulbs, assortment of interior screws and i even found a turbo kit while i was there.

Oct 29, 2012 | 04:25 PM

forddieselnewb

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The batteries checked ok and the belt has tension need to go see if alternator is shot. Is there a way to check the alt without going to advanced or some place like that?3 g seems to be the way to go from researching other posts I may go that way in the future thanks

Oct 29, 2012 | 04:36 PM

madpogue

Lead Driver

Joined: Oct 2003

Posts: 8,476

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From: Madison, WI

Any more info on this 3G upgrade? Is it just an alternator from a later truck, with a built-in regulator? What rewiring do you have to do? I just noticed the ammeter on the '85 kinda fluttering at idle; presuming that's the regulator, and I was just gonna change it out for good measure, but if a redux is not that expensive/difficult, I'm curious.

Oct 29, 2012 | 05:04 PM

hairyboxnoogle

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Joined: Apr 2008

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I dont remember all the specifics on it, but you want one from a mid 90s taurus, they have more amps and build power sooner, a more compact better looking case, and are internally regulated. Then you go to a crown vic and grab the "harness" as its longer in the crown vic and is easier to use in the trucks. (crown vic case is wrong to bolt into our trucks) IIRC its litterally bolt in, you ditch the external regulator and some wiring. I have the 3G done on mine and have never had a problem with it. Only setback is there is no provision for the factory amp guage, at least thats what i was told about my dentside

Oct 30, 2012 | 07:16 PM

forddieselnewb

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all is well

I replaced the volt regulator 22 dollars out the door at Advanced slapped it on and no idiot light and meter reads normal. This site rocks!

.
This was much easier and cheaper than a whole new alternator thankfully.

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Oct 30, 2012 | 07:41 PM

81Bronk36

Senior User

Joined: Nov 2007

Posts: 207

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A "3g" swap generally consists of a 130 amp 3 gen internally cooled and regulated alternator out of a 95 or so mustang or a well equipped merc sable or Taurus. You need to make sure it has the 6/12 o'clock ears, get the connector for the alt although they sell them for like 7 bucks at advance auto. swap the pulley from your old alt if its v belts and add a thin "spacer" the same size as the shaft to space it out far enough or it will rub the case.
You need a 150amp fuze, some 2-4 gauge wire, connectors and the green wire to turn on the alt. The white and yellow wire from the 3g harness goes on the positive stud as well with a connector. I probably spent about 80 bucks on everything, but that includes a stereo grade 150 amp fuze and 2 gauge welding wire, connectors and shrink wrap.

14 volts at all times running!
Once my alt got mud in it and I noticed it wasn't charging. I turned off the truck popped the hood and dumped a used 16.9oz bottle of dasani water that a guy I was with found under his backseat of his jeep on it. Let it sit for 30 minutes then fired it up and it worked fine for the rest of the time I had that truck.