Electrical issues

Discussion in 'Vehicles, Boats, Campers, & ATVs' started by mr4pt, Feb 13, 2018.

  1. mr4pt

    mr4pt Well-Known Member

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    Let me start by saying that I know less about auto mechanics then any 50-year-old man on the planet. My daughters car is draining the battery if it sits for more than a day or two without being used. I mean battery goes d-e-a-d, won’t even play the radio. It starts right back up when jumped, only a few minutes requires on cables. Will start and run fine after that, until she lets it sit over the weekend without using.
    So I assume there is a short somewhere but where do I even begin to look?
    Battery is about 2 months old, alternator maybe 4 months old.
     
  2. Saltydog

    Saltydog Well-Known Member

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    Wish you were closer... I take it as a personal challenge to seek out and find electrical shorts... :mad: not.
    Actually, I have been lucky locating a few..... it just takes some time and is a process of elimination.
    Gonna guess a mouse or packrat has been chewing on something.
    If you can run a tester, or a voltmeter, you might be able to isolate it and then look for the short.... for now I'd look for signs of rodent damage.
     

  3. Arkie_3_fan

    Arkie_3_fan Well-Known Member

    You mean like when they eat insulation off the firewall? IMG_9704.jpg
     
  4. Saltydog

    Saltydog Well-Known Member

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    Yup.... dats what I'm talking about.
    Don't look like he got in your wires though. At least I hope you were that lucky....
     
  5. QCDually5.9

    QCDually5.9 Well-Known Member

    That sounds like a bad regulator. Was the alternator replaced in an attempt to correct this problem or did this problem begin after the new alternator?
     
  6. mr4pt

    mr4pt Well-Known Member

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    After the new alternator. Alternator was definitely bad
     
  7. John Stiles

    John Stiles Ultimate Member 2007 Team Turkey Contest Winner

    What year model car? After dark, go outside and look at the car for any lights, sometimes brake lights will be on or the dome light. In older cars there is a separate regulator than in newer cars...some have the regulator in the alternator, some on the firewall, some newer have electronic regulators. I'm betting on a light staying on[even check the glove compartment, trunk light, and under-hood light]. Also check battery levels, and clean the terminals.
     
  8. Arkie_3_fan

    Arkie_3_fan Well-Known Member

    Actually got a fuel line.
    And I noticed the other day that the a/c was not lit up or functioning...
     
  9. Buck-Ridge

    Buck-Ridge Well-Known Member

    Some of the plastic insulation on Auto wiring is made of Soy now. Rodents like the taste of it. If you know how to test it you could probably figure out what is draining the battery by pulling fuses with the car turned off and test each circuit find what is draining the battery.
    Cheap and easy alternative would be to put a battery disconnect on the battery + post. And raise the hood and disconnect the battery each time it is to be parked a couple of days. 2 guys on my crew at work do this on their old crew change cars. We are parked for 2 weeks.
     
  10. QCDually5.9

    QCDually5.9 Well-Known Member

    What kind of vehicle are we working on? At this point, I'm leaning toward a bad regulator that came with the alternator. Was this an "autozone reman" style purchase?
     
  11. mr4pt

    mr4pt Well-Known Member

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    I haven’t looked at it yet but here is something odd. Yesterday am it started right up. Yesterday pm the battery was too weak to start it. This am it started right up
     
  12. mr4pt

    mr4pt Well-Known Member

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    Yes

    You’re saying the regulator is in the alternator?
     
  13. mr4pt

    mr4pt Well-Known Member

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    2005 Ford Explorer
     
  14. QCDually5.9

    QCDually5.9 Well-Known Member

    Yes, most regulators are built into the circuitry of the alternator. Dodge did have a regulator built into their ECMs at one point. I'm not familiar with Ford's way of doing things so I can't say for sure. I drove a dodge several years ago that did the exact thing you describe. It would drain the battery pretty quick at times. It was the regulator backfeeding the current while the motor was off. Which explained how it could drain the battery without catching something on fire.
     
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  15. QCDually5.9

    QCDually5.9 Well-Known Member

    If the regulator is in the alternator as suspected, a Reman unit will pass a basic bench test. The problem is not that the regulator isn't working. It's that a diode in the circuit is allowing current to pass in the wrong direction when the vehicle is not running.
     
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  16. QCDually5.9

    QCDually5.9 Well-Known Member

    And not that all reman units are not quality, but specific to autozone, their reman parts were known for having a high failure rate at one time. I don't know if that has changed. A call to a local alternator repair shop could be your best bet. Ask if the regulator is in the alternator of that model. They can test it for that failure and make any repairs needed.
     
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  17. Mr. Chitlin

    Mr. Chitlin Administrator Staff Member

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    Dang @QCDually5.9 ... that's some good info. We may let you hang around here a little longer. :D
     
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