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I need BOOOOST!!!!!!
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6,125 Posts
Discussion Starter #1
last week i noticed that my gauge cluster lights were flickering from bright to dim in rapid succession. i had a feeling that my alternator was about to let go. for the most part it did not flicker when the car was cold and usually would not start until i started to actually put the engine under load. the flicker was very noticeable in the headlights at night too. after a week the lights just went dim and never flickered back up and after about a mile or two the battery light comes on. the alternator quit charging... i made it home before the battery died, pulled the alternator and took it to advanced to have it tested and replaced under warranty and the alternator still tested as good. this leaves me with two conceivable options that i can see. either the pig tail is bad or the ECU/PCM is bad. just looking for confirmation or any other ideas as to what it could be. the plug that hooks up to the alternator looks just fine. the wires are not working their way out of the back side of the plug or anything. there is no copper wire visible anywhere from the plug back as far back in the wiring harness as i can trace it. there is no corrosion or anything visible in or on the plug. im going to go up to ford today and order another pig tail anyway and hope that there is something wrong with it that got past me but i dont have high hopes.
 

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21,250 Posts
WAIT!!!!!!

Don't go buy anything yet. [slap] you know better than purchasing parts before you've diagnosed the problem- that's why you subconsciously forced yourself to plea for help on FF. Like we know what's up or something.

Anyway, the coffee is hitting me, sorry about the humor. I have to give you old hands a hard time when I can y'know.

Check continuity between the positive cable end at the battery and the other end of the cable at the alternator. We just had another FF on here who fussed and fretted over a supposed alternator that was bad but tested good, and that's what he discovered. There is a, at least on his car, 175a fuse built into the cable. It can blow, go bad, or just screw up without warning. Check that before you spend your money and time on something you don't have to do.
 

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52 Posts
what is the pig tail? my car's alternator isnt working anymore either but i was told it was okay. what does it look like? can you post pictures maybe?
 

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I need BOOOOST!!!!!!
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6,125 Posts
Discussion Starter #4
??? 175amp inline fuse? ive never spotted that booger before. im not saying it isnt there, just that i dont remember seeing it. and what do you mean continuously check between the positive battery terminal and the other end at the alt? you mean poke it with a voltage tester right? i didnt ever test the voltage at the alternator since i wasnt getting any charge to the battery so it would stand to reason that if there is an inline fuse or even a short between the alt and battery that i wont see a voltage increase at the battery but would at the alternator. am i thinking right? im aweful tired and about to pass out for the day.
 

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By the pigtail, he's referring to the plug-in connector at the alternator. On the back of these alternators you should have 2 electrical connections- one bolted, the main hot from the alternator to the positive battery terminal- and the plug-in connector to the voltage regulator. Now technically, the term pigtail refers to any specialized connector on the end of some wiring, and that's how you repair broken connectors. You order a pigtail for your application, and wire it in place of the broken connector. When we're discussing alternators, then it means the VR wiring. When we're talking about injectors, then it's the injector connector pigtail- si?

You might have the same problem I described up there. Do you have a digital multi-meter to test electrical? If so, set it to resistance (ohms), put one lead on the positive battery terminal, or the end of the cable if it's disconnected from the battery, then the other end on the bolted cable at the alternator. You should find electrical continuity- or very low resistance (.01 or .1 ohms) with this test. If you find nothing (OL), then that cable is bad. The same thing goes if you find high resistance Mohms, or Kohms which might be possible depending on how the fuse went bad.
 

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??? 175amp inline fuse? ive never spotted that booger before. im not saying it isnt there, just that i dont remember seeing it. and what do you mean continuously check between the positive battery terminal and the other end at the alt? you mean poke it with a voltage tester right? i didnt ever test the voltage at the alternator since i wasnt getting any charge to the battery so it would stand to reason that if there is an inline fuse or even a short between the alt and battery that i wont see a voltage increase at the battery but would at the alternator. am i thinking right? im aweful tired and about to pass out for the day.
IT's built into the wiring from what I was told, so not easily visible. Think of it like a fusible link that's not visible. I just described how to do a continuity test in a response above. It depends on your meter really. Testing for voltage to ground at the alternator on the main hot should work as well if you're uncomfortable with your basic electrical testing skills- or just want to double check. With the engine off, you should have battery voltage there. Any loss between that reading and the battery voltage would indicate an increase in resistance. You should have no resistance on that wire- well basically none, like super low.

Go pass out man, sometimes it's best to sleep on it. Things might be clearer in the morning, and it's high time I get in the shower to head to work anyway. Best of luck.
 

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I need BOOOOST!!!!!!
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6,125 Posts
Discussion Starter #7
thanks alex. you always provide the best help. im going out to check it now if i can find the tester again...
 
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