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  • Electrical: Finding a short

    I have been thinking I had a bad Voltage regulator. My battery was pulled down all the way over about 3 days. I thought probably a bad battery as it was five years old. I bought a new one. I hooked up the positive cable and went to connect the ground. When I touched the ground cable to the ground post it threw a bug spark.

    I am not sure if what I did is correct but I took a voltmeter positive clip and attached it to the ground cable and touched the negative clip to the battery ground post. It showed 13 volts. Is that the correct way to verify a short?

    I then looked at the voltage regulator and saw that the largest coil points were not touching. I believe that is the reverse current relay isn't it? The other two points were closed.

    If I am correct, wouldn't that mean the voltage regulator is not my problem.

    When I put the new battery in and got the spark, I suspected the Voltage regulator so I filed the points and checked with the voltmeter again and a got a zero reading.

    Apparently that was not the problem as I am now getting a 13 volt reading again and the voltage regulator large coil points are open.

    The system is charging about 13 volts on the new battery when driving.

    I am now disconnecting the ground when I park until I find my problem.

    I obviously do not know what I am doing. Hopefully someone can steer me in the right direction. Thanks

  • #2
    Afronix;
    What you did will show 13 volts if anything is drawing power. The only item on a Studebaker that would draw any current when everything is off is the clock.
    Connect an Ammeter the same way you connected the volt meter; it will show the amount of current being used. The higher the reading the more current being used.Caution; If you have a spare dash board ammeter that goes to 30 amps or so; it will work fine for all but a dead short. if you had a dead short the wires going ot the short would be smoking. .
    To locate a short; with the key in the off position; start disconnecting items (pull the fuse). When you locate the short the current reading should decrease and if using a volt meter the voltage should drop to zero.
    You can also connect a bulb in place of the voltmeter. If there is no current draw the light will be off. The lower the resistance value of the short the brighter the light will be.
    Without touching the regulator's points disconnect both the battery terminal on the regulator. If the regulator or generator was at fault the meter should go to zero.
    Your charging voltage with the engine running at speed should be around 14 volts.
    Ron

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    • #3
      Go out at night and touch your battery and see if any lights come on and listen for any relays clickingI had similar issues and my dome light, map and engine lights were on. I had my horns disconnected however the horn relay was grounding and actuating with a distinctive click.

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      • #4
        I think what you have is not a short circuit but a unwanted current draw. Glove Compartment Light, Dome Light, Underhood Light, Trunk Light or Clock.

        The only items that have available power with the ignition OFF, are Head Lights, Parking Lights, Tail Lights, Stop Lights and Horn.
        The most likely of these is the Stop Lights, but I would think you would notice that.
        StudeRich
        Second Generation Stude Driver,
        Proud '54 Starliner Owner

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        • #5
          I had a draw on my 52 which would run the battery down if I left it connected. Like you, I would get a spark when I connected the battery. I searched all over for the source until one time when I reconnected the battery the defroster motor came on. The switch was in the on position (maybe since I bought the car), but because the Climatizer is not hooked up, I had not used it. I don't know if the motor was stuck or what, but after I turned off the switch the problem went away.
          "In the heart of Arkansas."
          Searcy, Arkansas
          1952 Commander 2 door. Really fine 259.
          1952 2R pickup

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          • #6
            You didn't mention the year and Model of your Studebaker, so I don't know what the wiring would be like, but on other makes of newer cars the wiring can be a nightmare. I made a simple tool to help find shorts. I'd connect it across the blown fuse, but on your Stude you could connect it in series with the battery cable as you did with your volt meter. The tool is just a 2 terminal flasher and headlight bulb connected in series. With this connect across the blown fuse, the short would make the headlight flash off and on. I'd then use an inductive ammeter or hold a compass next to the wires in question. I'd move the meter (or compass) along the wire, and as soon as it stopped moving with each flash, then I had just gone past the short.

            My neighbor had a similar problem the other day on his 1949 Jeepster. As soon as the battery cable was connected it made a small spark. I found the speedometer cable was touching one of the overdrive relay contacts, which kicked on the relay and energized the overdrive solenoid. Proper positioning of the speedometer cable fixed the problem.

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            • #7
              Originally posted by 52-fan View Post
              I had a draw on my 52 which would run the battery down if I left it connected. Like you, I would get a spark when I connected the battery. I searched all over for the source until one time when I reconnected the battery the defroster motor came on. The switch was in the on position (maybe since I bought the car), but because the Climatizer is not hooked up, I had not used it. I don't know if the motor was stuck or what, but after I turned off the switch the problem went away.
              You need to move the Power wire for your Defroster Motor from the "Batt." Terminal of your Ignition Switch to the "ACC" Terminal, it is SUPPOSED to be Switch controlled NOT always Hot!
              StudeRich
              Second Generation Stude Driver,
              Proud '54 Starliner Owner

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              • #8
                The body shop that sold our 1960 HAwk to my wife said that he disconnected the battery because the clock made it run down.

                The clock only draws current briefly once in a while to wind itself up.

                The real problem was the wiper motor had fused some of its contacts. Perhaps from being stalled and left on, or ????

                The wiring diagram was pretty simple, and the fuses are few and far between, so as others said, testing the circuits was pretty easy.

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