My volts are going wacky...help

Discussion in 'Volvo Forum' started by fireba11, Sep 19, 2013.

  1. Sep 19, 2013 #1
    fireba11

    fireba11 Heavy Load Member

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    Tracy City, TN
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    Need some mechanical help!! On my 2004 Volvo with a cummins engine. My volt gauge has been going wacky from 11.5 volts to 13.5 volts for no reason. My inverter shows a constant 14.7 volts as we go down the road but the volt gauge is all over the map. Whe the voltage on the gauge goes below 12 volts the tractor low voltage protection beeps and starts to shut everything down in the cab. Warning on dash for light control module comes on whenever I start the truck but all the lights are working fine. Any idea what is the matter would be appreciated!

    BTW....I have replaced all 4 batteries and the Alternator in the past 2 months and have looked for loose wiring but haven't found any.
     
    fireba11, Sep 19, 2013
    fireba11, Sep 19, 2013
    #1
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  3. Sep 19, 2013 #2
    Pound Puppy

    Pound Puppy Heavy Load Member

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    I would re check the alternator for possible defects, especially if it was a reman.
     
    Pound Puppy, Sep 19, 2013
    Pound Puppy, Sep 19, 2013
    #2
    luvtotruck Thanks this.
  4. Sep 19, 2013 #3
    morr2fab

    morr2fab Medium Load Member

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    Get a maintenance person.
     
    morr2fab, Sep 19, 2013
    morr2fab, Sep 19, 2013
    #3
  5. Sep 19, 2013 #4
    CondoCruiser

    CondoCruiser The Legend

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    The inverter is connected straight to the batteries so it will show different from a truck wiring problem. If it's showing a steady 14.5V and the gauge is bouncing I would say the alternator is okay.

    Most likely you have a short in progress related to the module. The vibration of the truck running is making the short touch/not touch. It could be the light control module itself if it is throwing a warning. Modern vehicles have little brain boxes for certain circuits. Guessing can get expensive. I would get an experienced mechanic on it. Hooking the laptop up might isolate the problem. Either that or it's getting the trusty multimeter out.
     
    CondoCruiser, Sep 19, 2013
    CondoCruiser, Sep 19, 2013
    #4
    fireba11 Thanks this.
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