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Alt not charging battery

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by PetaKane, Sep 10, 2002.

  1. PetaKane

    PetaKane 1/2 ton status

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    I've got a green wire going to the alt plug, and red wire that used to go to the alt plug, it's a thicker gauge, maybe 10 with a little black thing right before the alt plug (fuse?). And I've got the charging wire from the alt to battery. I'm only getting 12.2 volts from my meter. I hooked up the old red wire directly to the battery, the one that used to plug into the alt. Does anybody know why it's not charging?
     
  2. shane74

    shane74 1/2 ton status

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    is your alt dead? if not, is your batt. dead? I ran into the exact same thing a couple weeks ago. I had the alt tested. It was bad so I replaced it. Then a couple days later the batt. went bad too. So I replaced the alt., batt., and cables. Cost $100 but it should be good to go for awhile.
     
  3. PetaKane

    PetaKane 1/2 ton status

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    Alt is new, and so is batt. I'm thinking that red wire is supposed to be hooked up to the alt plug but I wanna make sure before I go hooking it back up and burning something up. The alt is a 250 amp so I can't replace as easy as I could my old alt.
     
  4. or2play

    or2play 1/2 ton status

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    Have you traced the wiring back from the alternator to the battery? I've been having ongoing alternator problems lately myself. Make sure you check everything. The smallest little connector or break in the insulation can cause you problems.
     
  5. 350S10NJ

    350S10NJ Registered Member

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    The 10 gauge red wire is the field wire and must be hooked up (it tells the alt. how much to charge) the green wire is what turns the alt. on at lower rpms (under 1400).
    the field wire can be run to the positive stud on the back of the alt. where the wire that goes to the batt. is. I do all mine that way just to keep 1 less wire away from the heat of the headers.
     
  6. PetaKane

    PetaKane 1/2 ton status

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    Okay, I see now. Where does the red field wire eventually end up? And what else is it hooked up to along the way? If someone can help with this part, I think it'll be up and running as soon as I get home from work. Thanks for everybody's help
     
  7. SkulzNBonz

    SkulzNBonz 1/2 ton status

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    If you need to, you can come over and look at mine after work. I think you're right down the street from me. I think my wife is helping her sister move, so I have some free time to tinker. I was having a prob. w/ my alt. not charging, turned out to be a wire shorting out. Send me a PM and let me know.

    John
     

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