Small arc, when reinstalling positive battery cable?

Electrical & Ignition

  1. koosh

    koosh Well-Known Member

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    I been noticing whenever i remove tbe positive battery cable to work on electrical issues, when i go to reinstall positive cable, i get a small arc, which i believe means something is drawing current?
    Nothing is on in the car, gonna need help on how to find it?
     
  2. jprather

    jprather Well-Known Member

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    silly question.. are car doors open?? interior lights maybe ?
     
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    • 67belvedere/225

      67belvedere/225 FBBO Gold Member FBBO Gold Member

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      aftermarket radio with memory. alternator could have a bad diode
       
    • Mike67

      Mike67 FBBO Gold Member FBBO Gold Member

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      Pull one fuse at a time until it stops. If you have Multimeter that can read DC amps, pull the fuse and place a lead on each of the fuse holders (series) until you find the circuit that is drawing curent and then go frim there.
       
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      • PP1RT

        PP1RT Well-Known Member

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        You should always remove the ground cable first and hook it up last.
         
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        • koosh

          koosh Well-Known Member

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          Doors should not matter since i pulled dome light out?
           
        • Don Frelier

          Don Frelier FBBO Gold Member FBBO Gold Member

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          Do you have a working horn? If not, the button in the wheel can make the horn relay pull in constantly.
          So a slight draw with apparently nothing on.
           
        • koosh

          koosh Well-Known Member

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          I DO have aftermarket radio, and amp, but they are not on unless key is on?
           
        • PP1RT

          PP1RT Well-Known Member

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          They draw a trickle for memory. One wire is hooked to a constant hot. Another to a switched hot.
           
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          • koosh

            koosh Well-Known Member

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            Horn works fine.... (aftermarket steering wheel, new horn button, and new signal light harness)
             
          • koosh

            koosh Well-Known Member

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            Im gonna have to get one of those...my meter only reads voltage and ohms
             
          • koosh

            koosh Well-Known Member

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            They draw enough for a small arc?
             
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            • koosh

              koosh Well-Known Member

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              Why is that?
               
            • PP1RT

              PP1RT Well-Known Member

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              Any draw can. Disconnect that hot wire and test again. By removing the ground cable at the battery first and hooking it up last eliminates arcing.
               
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              • koosh

                koosh Well-Known Member

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                Thanks!
                 
              • PP1RT

                PP1RT Well-Known Member

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                On a neg ground system elec flows from neg to pos thru the systems back to ground. The elec supply is stored in the battery. It cannot flow from the battery until the ground is hooked up. When you are hooking and unhooking the positive first you are playing with a live circuit midstream. By hooking and unhooking the ground first you are working before the power source and eliminating the arc.
                 
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                • koosh

                  koosh Well-Known Member

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                  Thanks a bunch!
                   
                • 67belvedere/225

                  67belvedere/225 FBBO Gold Member FBBO Gold Member

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                  the reason being that you unhook the negative first is that the body is use as ground. so if you have the wrench in your hand and you touch the body nothing happens
                  but image your unscrewing the positive and you touch the body you can cause a huge spark and melt down
                   
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                  • typhoontx

                    typhoontx Active Member

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                    Separate audio amps and the radio's have capacitors in them that charge up when you first connect power, they can cause a small spark when connecting a battery back up even though they are turned off. The thing to check is how much current is being drawn constantly off the battery when everything is turned off.
                    The clock/memory in the radio should only draw a few milliamps. if its above 40-50 milliamps you will need to start pulling fuses and disconnecting things to pin down the draw. Main thing is if you car will crank just fine after sitting for a month or 2 its not a concern, However, if you know the car is going to sit for more than a month either disconnect the battery or better yet is to disconnect the battery and connect a small battery maintainer to keep it charged no matter what the static draw is off the battery
                     
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                    • koosh

                      koosh Well-Known Member

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                      Agreed! Great advice!