Charging System
Thread Starter
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Mountain Pass
Joined: Jul 2004
Posts: 229
Likes: 0
From: San Diego, CA
Charging System
On my 99 F250 7.3 my battery idiot lite started flickering on and off a couple of days ago. When I first start it in the morning it will stay on for about a minute and once i start moving it goes off. Today it started flickering on and off at a stop light.
Is it time to replace the alternator?
brian
Is it time to replace the alternator?
brian
Fleet Owner
Joined: Jun 2004
Posts: 25,090
Likes: 1,111
From: Rio Rico, AZ.
Originally Posted by briank
On my 99 F250 7.3 my battery idiot lite started flickering on and off a couple of days ago. When I first start it in the morning it will stay on for about a minute and once i start moving it goes off. Today it started flickering on and off at a stop light.
Is it time to replace the alternator?
brian
Is it time to replace the alternator?
brian
Post Fiend
Joined: Jul 2005
Posts: 14,582
Likes: 12
From: 21791
sounds to me like the AC sine wave rectifier diodes in the rectifier bridge in the rear of the alternator are leaking, causing an AC signal to return to the battery, which slowly drains them over night, and once you start it up in the morning, it recharges the batteries.
when i took my truck into school to test the charging system, i did an AC leakage test. use a digital multimeter set on Volts AC, placing the positive lead on the alternator output, and the negative lead on the alternator housing (ground). the reading should be less than .3V, showing that the diodes are stopping AC current. on mine, the reading was like .06V, which was really good. im guessing this is your problem, if your truck still starts quickly when it's warm, and the alternator has had a chance to recharge the batteries.
the alternator is not field-servicable, so you'll need a new one. if you would like to donate the bad alternator to my school, PM me and we can talk about it. we are in need of dummy alternators as learning tools. Thanks.
when i took my truck into school to test the charging system, i did an AC leakage test. use a digital multimeter set on Volts AC, placing the positive lead on the alternator output, and the negative lead on the alternator housing (ground). the reading should be less than .3V, showing that the diodes are stopping AC current. on mine, the reading was like .06V, which was really good. im guessing this is your problem, if your truck still starts quickly when it's warm, and the alternator has had a chance to recharge the batteries.
the alternator is not field-servicable, so you'll need a new one. if you would like to donate the bad alternator to my school, PM me and we can talk about it. we are in need of dummy alternators as learning tools. Thanks.
Hotshot
Joined: Jan 2002
Posts: 17,988
Likes: 207
From: La La Land
Originally Posted by strokin_it7.3
The alternator is not field-servicable, so you'll need a new one.
Pully pullers are cheap on Fleabay.
This way, I KNOW my alternator has been "gone through" the right way.
Pop
Elder User
Joined: Oct 2005
Posts: 786
Likes: 0
From: Reno nv
Except for polishing the commutator, and true-ing it, Springerpop is doing what the local rebuilder usually does to all them cores they got.
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Post Fiend
Joined: Jul 2005
Posts: 14,582
Likes: 12
From: 21791
we have a commutator lathe at school, it is a neat piece of machinery. yep that is right, truing the commutator, polishing the slip rings, and replacing brushes and testing the diode bridge, repacking bearings is about all that is in an alternator rebuild.
i thought they weren't field serviceable because i didnt know of a place that could sell individual parts for a powerstroke alternator.
i thought they weren't field serviceable because i didnt know of a place that could sell individual parts for a powerstroke alternator.
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Hotshot
Joined: Jan 2002
Posts: 17,988
Likes: 207
From: La La Land
Having it apart will give me the opportunity to see if the rotor needs truing, and I always go over the slip rings with crocus cloth, just for good measure. I even did that to the teenie-tiny motors in my door lock actuators when I did the "tin foil mod".
Pop
Pop
Junior User
Joined: Sep 2006
Posts: 52
Likes: 0
because of the price of the new or re-man alt. I made up a bracket and used a delco remy 22si pad style alt at the dealership it was over $300.00 this 22 si pad style was $115.00 and a full 2 year warranty through International truck. I can post a pic to show what I've done you may have to re work the wiring at the back of the alt but it's easy let me know.. Herman
Thread Starter
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Mountain Pass
Joined: Jul 2004
Posts: 229
Likes: 0
From: San Diego, CA
Herman2001,
Please post a pic of the set up. I was looking at my gauges and my alt gauge shows it to be charging. But I am not sure what is up with the battery light. Thanks brian
Please post a pic of the set up. I was looking at my gauges and my alt gauge shows it to be charging. But I am not sure what is up with the battery light. Thanks brian
Senior User
Joined: Feb 2006
Posts: 265
Likes: 0
From: Candler, NC
My '99 is doing almost exactly the same thing as briank's. When yall were saying the connection is fried on the back do you mean on the alternator or the plug in the wiring harness, meaning could i just replace that plug or is it the alternator? thanks