Help! Wifes truck has voltage issues??...

Discussion in 'GM Electrical Tech' started by SHRIKE, Aug 19, 2010.


    SHRIKE New Member

    2003 Silverado 1500 V8, steel block alum heads... I have not checked the truck yet, I'm waiting for the sun to come up... She (the truck) would not start and we assumed it was just another battery, we put another battery in and everything seemed ok. However, we did not for a test run. Then this morning around 5am as Wifey headed out to work she reports the truck has low voltage at idle and 13.5 under way.... I will check the tech reports but, is the voltage reg inside the altinator on these trucks?? Do you guys think the code reader at the parts store will read it??... Thanks for any help or advice...
  2. MightyMax

    MightyMax Rockstar 100 Posts

    Most likely the regulator is built into the alternator.

    Unless a CEL/SES pops up on the dash, I don't believe their will be any codes in the on-board computer.

    You can run to Adv. Auto or Auto Zone and they will check your alternator.....
    Or pull the alternator and take it down and let them bench it for you.....
    Then you can at least rule out the battery and alternator.

    SHRIKE New Member

    Well, it seems to be generating voltage, the gauge says it's pumping out 14v. But when the rpm drops to idle, the truck surges and clearly is not happy. It has been a really good truck, this is the first thing in over 200K. I will run it down and see if they can get a code off it....
  4. MightyMax

    MightyMax Rockstar 100 Posts

    So it seems it is not the charging system.??

    Seems you are idiling lower than should be....??

    SHRIKE New Member

    Jeez man... Now it's running pefect?? Must have been unhappy for a few minutes after the battery swap??... I will keep an eye out and report back. Intermitten stuff is a real chase, I hope it fixed
  6. MightyMax

    MightyMax Rockstar 100 Posts

    Did you move wires around?
    If so, then it might be a wiring problem and that is why it acted up.

    Might do the same when it gets warm.

    Good Luck
  7. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    When ever you remove the battery cables and reconnect them the ecm goe's through a relearn process for a few miles.

    ---------- Post added at 11:58 AM ---------- Previous post was at 11:55 AM ----------

    I forgot to mention on my last post, some trucks are dumber than others so they take longer to relearn.

    SHRIKE New Member Well, I guess she got it figured out. She ran 60 miles out and 60 miles back, no problem.. (Knock on

Share This Page

Newest Gallery Photos