Pretty sure my alternator just went out. Need Advice

Discussion in 'Engine & Drivetrain' started by JJ93, Oct 13, 2019.

  1. JJ93

    JJ93 TYF Newbie

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    Hi everyone! I'm pretty sure my alternator just went out, but I want to see what you guys think.

    I left this morning to head to the upper peninsula for a few days. The truck was running fantastic. About 25 miles after crossing the mackinac bridge my battery light came on, and my volts were showing about 12. I pulled off the road and restarted the truck, and after a minute the volts went back to 14. I drove another 10 minutes and then the light came on again for the battery, and my volts were dropping. Seeing as how I had no phone signal in the middle of the wilderness, I decided to turn off all electronics and press on for another 25 miles until I hit the next town (only to find out all the parts stores within a 1 hour drive were closed today). The truck made it but was obviously getting low on charge. So here I sit in a hotel room until tomorrow morning when the parts stores open up.

    Do my symptoms sound like a failing alternator to you guys? I'm assuming my '01 Suburban has the 130 amp alternator?

    Thanks in advance everyone!
     
    Last edited: Oct 13, 2019
  2. Scottydoggs

    Scottydoggs Full Access Member

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    id check that the battery cables are tight. you can also take the belt off and hand spin the alt pulley. if its really hard to turn, or you can hear it or feel it grinding. its bad.

    also get the battery load tested before you buy a alternator. with the battery tester tool at the parts store, most have one for free use. you can test the load the battery is good for, and see volts of the battery engine off, and running, off you want to see 12, but that might be low due to the bad alt. running you want to see 13-14 volts. if you dont get that 13-14 running the alt is failed for sure.

    only good thing here is the battery or the alt is a quick swap in the parking lot with minimal tools.
     
  3. JJ93

    JJ93 TYF Newbie

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    Thanks man. I will check those things for sure. I haven't verified the voltage with a voltmeter but I did check with the torque app on my phone and after running for a bit without the alternator it was starting to drop below 12 volts. The more I think about it the more it is sounding like the alternator. I did hear a very minor grinding coming from what sounds like the alternator area that was getting worse.

    I guess that verifies it then haha.

    Thanks for your advice!
     
  4. OneofFew

    OneofFew Full Access Member

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    Mine did the same way when the regulator went bad in the alternator.
     
  5. HiHoeSilver

    HiHoeSilver Away!

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    Your alternator will be specified by the K code on your RPO sticker in the glove box.
     
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  6. JJ93

    JJ93 TYF Newbie

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    Thanks for that!
     
  7. ivin74

    ivin74 05 Yukon Denali

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    Check the fuseable link that goes from the alt to the battery, I had that burn out on my silverado and had similar symptoms.

     
  8. Rocket Man

    Rocket Man Build It Better

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    Update us on what you find out this morning.
     
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  9. JJ93

    JJ93 TYF Newbie

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    Sorry guys, I've been driving all day. The alternator did test bad, it wasn't putting out anything at all. I installed a brand new one in the parking lot at the auto parts store (in the snow lol) and it has been running great!!

    Thanks everyone for the suggestions!

    Edit: I'm surprised how far I could drive on just the battery lol. From the time my alternator went out until I finally was able to replace it i drove about 38 miles. I never want to do that again haha
     
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  10. Rocket Man

    Rocket Man Build It Better

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    Thanks for following up. Glad you got it fixed and back on the road.
     
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