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Old Oct 19, 2015 | 12:10 PM
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Default alternator problems

So the other week my alternator went out again. I went to autozone got anoyher one. But aftering putting in when i started the car it was charging at 18 volts. So i thought it was a bad alternator, so i went and got another one but its doing the same thing. Any ideas on what it could be? A few month back i replaced the power plug that goes to the alternator, could it be it? Thank you!!!
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Old Oct 19, 2015 | 12:19 PM
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Check pcm for alternator related trouble codes.
Has the 18v charging shown up after you replaced the pigtail.
Did you use a voltmeter to verify the actual output voltage.

If it's wired correct there arent any codes stored and it's putting out that high of voltage pull the alternator have them hook it up and verify it's output voltage on their tester.
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Old Oct 19, 2015 | 01:57 PM
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Originally Posted by 01WS6/tamu
Check pcm for alternator related trouble codes.
Has the 18v charging shown up after you replaced the pigtail.
Did you use a voltmeter to verify the actual output voltage.

If it's wired correct there arent any codes stored and it's putting out that high of voltage pull the alternator have them hook it up and verify it's output voltage on their tester.
Excellent advice, would be my suggestions as well.
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Old Oct 19, 2015 | 02:19 PM
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Originally Posted by 01WS6/tamu
Check pcm for alternator related trouble codes.
Has the 18v charging shown up after you replaced the pigtail.
Did you use a voltmeter to verify the actual output voltage.

If it's wired correct there arent any codes stored and it's putting out that high of voltage pull the alternator have them hook it up and verify it's output voltage on their tester.
I replaced the pigtail together with an alternator in august and they worked fine until two weeks ago. I did use the voltmeter to check the voltage and it would go up to like 17+ volts. I will check the pcm codes later on today.
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Old Oct 20, 2015 | 06:43 PM
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Originally Posted by vlad1995
I replaced the pigtail together with an alternator in august and they worked fine until two weeks ago. I did use the voltmeter to check the voltage and it would go up to like 17+ volts. I will check the pcm codes later on today.
I didnt get a chance to check the pcm, but i noticed that someone taoed together the 3 extra wires that are on the pigtail. Could that be causing the problem? I just took the tape off and seperated the cables and started the car. The volt gauge is showing right under the 4th bar on the right.
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Old Oct 20, 2015 | 07:51 PM
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Originally Posted by vlad1995
I didnt get a chance to check the pcm, but i noticed that someone taoed together the 3 extra wires that are on the pigtail. Could that be causing the problem?
Yes, that is bad. Even though those wires are not used on the car, I recall that the regulator on the alternator still has them live.

I forget what they do/are for, but crossing those terminals on the alternator could cause problems. You should just have one wire hooked up to the voltage regulator connector on the alternator.
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Old Oct 21, 2015 | 12:37 PM
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Originally Posted by wssix99
Yes, that is bad. Even though those wires are not used on the car, I recall that the regulator on the alternator still has them live.

I forget what they do/are for, but crossing those terminals on the alternator could cause problems. You should just have one wire hooked up to the voltage regulator connector on the alternator.
Yeah i crimped off the extra 3 wires so they dont touch anything. So far the car been running good.
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Old Oct 21, 2015 | 06:50 PM
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I look looked up the regulator specs and didn't find a definitive source - but it looks like one of those three sends an alternator RPM signal, one is for testing the output voltage, and the other is a control wire. So tying them together could make really odd things happen...
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Old Oct 23, 2015 | 07:48 PM
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Originally Posted by wssix99
I look looked up the regulator specs and didn't find a definitive source - but it looks like one of those three sends an alternator RPM signal, one is for testing the output voltage, and the other is a control wire. So tying them together could make really odd things happen...
So maybe the rpm signal was the reason why it was going crazy. But it's been doing pretty good so far.
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