After installing a rebuilt alternator, the battery gauge reading started to drop and the car shut off, why?

Tiny
BEASTY83
  • MEMBER
  • 2000 FORD MUSTANG
  • 3.8L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 2,100,000 MILES
I recently purchased a refurbished alternator, after installing it I started the car and then the car shut off shortly after. I had to jump to get it started and I had the alternator wires disconnected and then I connected the alternator wires and then the battery gauge started to drop, and the car shut off. What do you recommend? Thank you
Saturday, August 13th, 2022 AT 11:03 PM

9 Replies

Tiny
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Hello,

The alternator could have a faulty voltage regulator and not able to provide proper output to the battery.
Did you have the same issue before replacing the alternator?

Testing the alternator should be the first step.
It should have output of 13.6V - 15.2V to the battery while in idle.

Take a look at this helpful guide:

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Let me know of any questions.
Thank you.
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Sunday, August 14th, 2022 AT 4:07 PM
Tiny
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I had my old alternator tested and it was good and the refurbished one was good too. Should I check the fuses, and which one am I looking for?
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Tuesday, August 16th, 2022 AT 9:44 PM
Tiny
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Just to make sure, did the alternator get tested out of the vehicle or while it was on the vehicle.

There should be a fusible link located in the fuse box under the hood. If the link is blown then the alternator will be unable to charge the battery.

See wiring schematics below.
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Wednesday, August 17th, 2022 AT 5:53 PM
Tiny
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It got tested at AutoZone with the alternator out of the car.
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Sunday, August 21st, 2022 AT 9:12 PM
Tiny
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Check for the fusible links and let me know what you find.
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Sunday, August 21st, 2022 AT 10:31 PM
Tiny
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Okay, problem fixed. It was the fusible links. Thank God. Thank ya'll.
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Thursday, September 1st, 2022 AT 3:48 PM
Tiny
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You are welcome!
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Thursday, September 1st, 2022 AT 8:18 PM
Tiny
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Yes, my #20 fuse Gen is still blowing, and it blows after I drive for like 30 minutes. Are there any other fuses I need to check or what do I do?
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Wednesday, September 28th, 2022 AT 6:58 PM
Tiny
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You could have a wiring issue. First check is to do a visual check of the ground wire. You can use the wiring schematics above for your reference.

Here is a helpful guide on how to check wiring:

https://www.2carpros.com/articles/how-to-check-wiring
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Friday, September 30th, 2022 AT 9:05 PM

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