No power from alternator, why?

  #1  
Old 09-14-2009, 11:27 PM
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Exclamation No power from alternator, why?

I recently started having charging issues along with my battery light flickering then shortly after becoming solid. I thought my battery was weak so i replaced it. Nothing.. Then figured it was my alternator so i replaced it also... still nothing.


I checked every fuse under the hood and tryed to by-pass the mega fuse that is inline from batt to alt. Nothing..

I disconnected my power from the alternator and tested and it was dead. as of now neither alternator will produce. What gives?

Ive check my grounds from batt to firewall, starter and chassis ground and all are clean and tight.

To add to the story i took both alternators in and had them tested and they both came back perfectly fine. Im not sure where to go from here.

If someone has some in depth ideas please hook me up. As im kinda stranded.
 
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Old 09-14-2009, 11:46 PM
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Did you check the fuse for the rectifier field ?

I think this is a separate fuse on your MY ( 99 or 00 + MY it is in the Central Junction Box ).
 
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Old 09-14-2009, 11:52 PM
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Uh im not sure. I checked all fuses in the big fuse block under the hood. perhaps thats the ticket. where can i locate this?
 
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Old 09-15-2009, 12:33 AM
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Last edited by SSCULLY; 09-15-2009 at 12:44 AM.
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Old 09-15-2009, 01:24 AM
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Oh ok... Yes i did.

I replaced the small fuse #3 and also tried by-passing the mega fuse #2 by hooking the wires directly to each other.

I wanna say that it was kinda slow happening, i noticed i had issues when my volt gauge dropped down some and my battery light was flashing from time to time. Now its on constant and running off only my battery.
 

Last edited by kievitk; 09-15-2009 at 01:26 AM. Reason: added more info
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Old 09-15-2009, 04:57 AM
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The alternator is most likley toast. You could pull the regulator real quick and make sure you still have brushes or check them to make sure their not stuck like these where -





And here they are after I cleaned them up. They sprung right away. Dirt particles had jammed them.

 

Last edited by jbrew; 07-14-2010 at 02:27 AM.
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Old 09-15-2009, 08:30 AM
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Well at this point in time im going to consider everything cause i have no clue any more. It would really trip me out if it was the alternator though.

After this all happened, i did think it was the alternator so i replaced it (only bout year or so old) with one that was supposedly good from local auto wrecker. Did not make a difference so now im thinking maybe i have two bad alternators. well i went and had them both test and everything tested good. (rectifier, regulator and what not) so thats where i stand. So do i have two bad alternators by chance or maybe two good ones
 
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Old 09-15-2009, 12:41 PM
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Wait a minute, did you poke around the harness. I had to rebuild the harness TWICE in my 98. Slipped my mind, the Yellow and the Orange wires would wear out, get brittle and sever inside it's wrapping. I have a pic of that somewhere, but can't find it ?? OH, I know where those are lol, -on line, -here's one I've re-done -

http://picasaweb.google.com/jbrew393...23685771861730





 

Last edited by Bluejay; 12-19-2009 at 01:18 AM.
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Old 09-15-2009, 04:07 PM
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I haven't inspected the whole harness just checked all the plug ends. Where did you get all the new hardware to rebuild your harness?

I'm still not sure where to turn now. maybe alternator still... maybe the harness..

Whats the "excite" wire? 2 people said that maybe thats what it was. In the mean time ill check out the harness a little better.
 
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Old 09-15-2009, 05:23 PM
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Originally Posted by kievitk
...<snip>....
Whats the "excite" wire? 2 people said that maybe that's what it was. ...<snip>....
I think they are referring to the alternator field circuit.

This is the Orange w/ light blue stripe wire jbrew posted about, that goes to the 20 A fuse next to the mega fuses.

Best to remove the harness and check for cracks in the insulation, ohm meter the wire out to make sure it is good. Remember to move it around while you have the meter on there, to make sure it is not an intermittent symptom
 
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Old 09-18-2009, 11:42 PM
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Originally Posted by kievitk
After this all happened, i did think it was the alternator so i replaced it (only bout year or so old) with one that was supposedly good from local auto wrecker. Did not make a difference so now im thinking maybe i have two bad alternators. well i went and had them both test and everything tested good. (rectifier, regulator and what not) so thats where i stand. So do i have two bad alternators by chance or maybe two good ones
WAIT A SECOND... you bought a used alternator that was "suppose to be good" did you check what it would cost to rebuild a alternator around here it cost about 30 bucks to have one rebuilt to brand new specks I would say that you bought a bad alternator
 
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Old 09-21-2009, 07:01 PM
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Yeah just as i said before it was used but they said it was good, AND it was tested along with my other alternator. Both alternators came back as good and the print out to prove it.

Now to SSCULYs post... I have not got around to pulling the wiring harness or the alternator to check for damaged wires or problems with the brushes but will soon and post my results.

Im not saying that the chance of it being the alternator doesnt exist, its just i dont want to buy a third one and try that just yet, specially after having the two i have test good. :-/
 

Last edited by kievitk; 09-21-2009 at 07:05 PM.
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Old 09-24-2009, 10:51 PM
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Im with Brew.....I had a dead superduty that was due to a bad link in the harness along the right fender
 


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