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  1. #1

    Default Help Needed on Volt Meter

    2009 Silverado Ext cab 4.8L

    I noticed some of the time my volt meter is reading about 12v other times 14v and at start up 14.2v. I assumed the alternator brushes were likely getting worn (90K miles), but then I read the in the manual while in the fuel economy mode it can read lower, and while running it is also normal for the reading to rise or drop?

    Some of the time I know it was not in the economy mode while reading around 12v. That doesn't seem normal to me, while running I always thought the alternator should be at 14.2. Is there a type of clutch on the alt now similar to the ac to kick on and off as needed?
    Confused
    Last edited by 71Stage1Conv; 01-13-2014 at 07:06 PM.

  2. #2

    Default

    Letting us know what truck and alternator combo your taking about would help us answer your question.

    GM has been using "smart" alternators for awhile. The '07 and up trucks have an alt that will adjust the output based upon load demand.
    Ray

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  3. #3

    Default

    Its an 09, so I guess it is the 145amp smart alt. How does it work? When it does go south, should I upgrade to the 160amp

  4. #4

    Default

    Quote Originally Posted by 71Stage1Conv View Post
    How does it work?
    http://jcwnapa.com/wp-content/upload...TE_0213_TE.pdf

    Quote Originally Posted by 71Stage1Conv View Post
    should I upgrade to the 160amp
    If the original alt is working as designed, why do you think you need a bigger one?
    Ray

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  5. #5

    Default

    I have added a few electrical options, plus from what I read the computer would only regulate the output anyway. All it would do is make more recharging power available only when needed without waiting energy, hence why not?

    Thanks for the napa link!

  6. #6

    Default

    Quote Originally Posted by 71Stage1Conv View Post
    from what I read the computer would only regulate the output anyway.
    That is all any alternator will do, they are designed to regulate the output. If the current alt is not reaching it's max output, a higher output alt will act no differently.

    But hey, it's your money.
    Ray

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

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