1. Welcome to Tacoma World!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tacoma discussion topics
    • Communicate privately with other Tacoma owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

Alternator is bad?

Discussion in '2nd Gen. Tacomas (2005-2015)' started by Will Ennis, Nov 30, 2015.

  1. Nov 30, 2015 at 10:14 AM
    #1
    Will Ennis

    Will Ennis [OP] New Member

    Joined:
    Jun 6, 2015
    Member:
    #156874
    Messages:
    3
    Gender:
    Male
    First Name:
    Will
    Vehicle:
    2013 Silver Tacoma TRD Sport 4.0l V6, 2x2, short bed
    Bone Stock
    I'm new to this forum and recently bought a Certified Tocoma with 35K miles from a dealership in town. I drove is 6K miles and noticed the battery was getting weaker. I took it to Auto Zone and bought a new battery and had them test the alternator. It tested bad. Tech says its not charging the battery like it should. I called a dealership in town and they are telling me to bring it in to have the problem diagnosed. If the alternator is tested bad at the dealer then my warranty company should cover the parts and labor for a $50 deductible fee. My question is: are there any worries about the part they put in my truck? I've never heard of an alternator going bad after 41K miles on it. Especially in a truck with no modification ie: stereo, amplifiers, KC lamps, winch, etc. Any input would be greatly appreciated.
     
  2. Nov 30, 2015 at 11:54 AM
    #2
    username

    username Fluffer

    Joined:
    Oct 15, 2010
    Member:
    #44704
    Messages:
    6,067
    Pendleton, Or
    Vehicle:
    05 Taco with some crap welded to it
    mostly stock
    I broke an alternator case at around 50K miles, but mostly because it was submerged in mud and ingested some rocks/mud, bound up, and the case gave out. However, it still worked! I would suspect the high school drop outs working at auto zone don't know what they are doing. Go to walmart and get a multi-meter and see how many volts are at the battery terminals. Should be around 12.8V at rest, and near 14V when it's running. Most Tacoma's run around 13.8V at idle. Here is how the dealer does it, you can check it yourself very easily. http://www.customtacos.com/tech.old...f/06toyrm/06toypdf/06rmsrc/rm2006ta/02400.pdf
     
  3. Nov 30, 2015 at 4:03 PM
    #3
    devkurf

    devkurf Member at Large

    Joined:
    Jan 26, 2014
    Member:
    #121502
    Messages:
    909
    Gender:
    Male
    midwest
    Vehicle:
    2005
  4. Dec 1, 2015 at 5:03 AM
    #4
    Lester Lugnut

    Lester Lugnut Well-Known Member

    Joined:
    Mar 3, 2010
    Member:
    #32477
    Messages:
    2,822
    Gender:
    Male
    N of Mex-S of Canada-E of LA-W of NC
    Vehicle:
    '15 Tacoma PreRunner V6 SR5 Auto
    A simple way to test an alternator is to put the positive(red) lead from a voltage-ohm meter on the "B" terminal of the alternator. That's the "battery" terminal. Put the black lead from the VOM on the alternators case(ground). This of course is done with engine idling and everything off. Use the 20 setting on the DC voltage scale. If the motor is cold, you should see between 13.8V-14.2V. If it's warmer, you may see something around 13.4V

    The "B" terminal on the alternator usually has a round rubber plug over it that peels off by hand.

    Given that I have zero faith in car dealerships, I wouldn't be surprised if they replace your original Denso alternator with a POS from Auto Zone or some other mass marketer.
    Whenever mine bites the dust, I remove the alternator myself and take to a local electrical rebuilder. Just sayin'...
     
  5. Dec 1, 2015 at 10:07 AM
    #5
    george3

    george3 Well-Known Member

    Joined:
    Jun 8, 2008
    Member:
    #7173
    Messages:
    4,514
    New Jersey
    Vehicle:
    2008 2.7 Manual Trans Tacoma
    Seat belt beeper, Cabelas (Weathertech) floor liner gray, Covercraft Seat Savers in Taupe, Protecta Heavy Duty Rubber Truck Bed Mat, Pop n Lock PL5200, Pace Edwards Full Metal JackRabbit, Wolverine oil pan heater, Scangauge2, afe pro dry s filter, Remote Underbody 4 Piece LED Light Kit (White) used as Bed light, DIY Washable Cabin Air Filter, PA15-TOY, 4x4 Illuminated Switch, full synthetic, Redline Tuning Hood Support, Smittybilt Nerf Steps black powder-coated
     
  6. Dec 1, 2015 at 10:21 AM
    #6
    Lester Lugnut

    Lester Lugnut Well-Known Member

    Joined:
    Mar 3, 2010
    Member:
    #32477
    Messages:
    2,822
    Gender:
    Male
    N of Mex-S of Canada-E of LA-W of NC
    Vehicle:
    '15 Tacoma PreRunner V6 SR5 Auto
    george3:

    Answer to 1st question - I have more than 1 vehicle

    Answer to 2nd question - Placing the VOM leads on the alternator tests the alternator. Placing the VOM leads on the battery can give indication that the alternator is good, but testing the alternator itself is the best way to test that device. During my recent alternator issue('06 Avalon) - the battery was reading 12.3V with a cold engine. To be absolutely sure the alternator was the issue, I needed to test it. Had the alternator reading been good and the battery reading bad, I would have been looking at a bad battery.

    Pulling an alternator off a Toyota 2GR-FE engine('06Avalon) is a bit more of a pain than a Toyota 1GR-FE engine(Tacoma). The 2GR-FE is transverse mounted.
     
  7. Dec 1, 2015 at 10:28 AM
    #7
    george3

    george3 Well-Known Member

    Joined:
    Jun 8, 2008
    Member:
    #7173
    Messages:
    4,514
    New Jersey
    Vehicle:
    2008 2.7 Manual Trans Tacoma
    Seat belt beeper, Cabelas (Weathertech) floor liner gray, Covercraft Seat Savers in Taupe, Protecta Heavy Duty Rubber Truck Bed Mat, Pop n Lock PL5200, Pace Edwards Full Metal JackRabbit, Wolverine oil pan heater, Scangauge2, afe pro dry s filter, Remote Underbody 4 Piece LED Light Kit (White) used as Bed light, DIY Washable Cabin Air Filter, PA15-TOY, 4x4 Illuminated Switch, full synthetic, Redline Tuning Hood Support, Smittybilt Nerf Steps black powder-coated
    Thanks for the reply.
     

Products Discussed in

To Top