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Technical Need electrical help - '64 Galaxie w/ pulsing power draw...

Discussion in 'The Hokey Ass Message Board' started by Barsteel, Feb 11, 2015.

  1. Barsteel
    Joined: Oct 15, 2008
    Posts: 726

    from Monroe, CT

    Hello -

    Ever since I bought my '64 Galaxie, the battery had gone dead after a few days of sitting. I finally took some time today to take a look at it, and here's what I found:

    I charged the battery to take it out of the equation. It was still a little weak, but the car started.
    1-wire alternator putting out about 14.5V (battery was weak, so it's probably charging the battery)

    When I disconnected ground from the battery and put a test light between the battery and the cable with the ignition key in the off position and the dome light fuse pulled, I get a PULSING light, about the same frequency as a turn signal.

    I then pulled every fuse from the fuse panel, but found that none of the fuses would stop the draw.

    I think pulled the wires leading to the flasher (didn't know what else to do), but still got the draw..

    That's where I'm at now. I have to figure out how to pull the horn ring so that I can get at the signal switch to see what I can find there.

    Does anyone know of ANY other current draw that would draw in a pulsing pattern? I have somewhat of a clue as far as electrical systems go, but I am far from being an expert.

    I'd appreciate any help/insight.


  2. greaseyknight
    Joined: Sep 27, 2010
    Posts: 224

    from Burley WA

    Have you tried unplugging the alternator? I've heard they do weird things when they fail, even if they are still producing power. After that, I'd start tracing the wires between the battery and the fuse block to see if the previous owner added something.
  3. Is the original generator voltage regulator still in place? I've seen guys leave these in a conversion and they can cause a draw. Did you actually unplug the turn flasher? The wrong 2-prong flasher can cause a slow drain because it hooks up 'backwards' internally (I actually had this problem on a '64 Comet). But it sounds like somebody has been at the wiring, these can be a real challenge to troubleshoot...
  4. Does the car have a factory installed clock, or maybe a later model radio with maybe a digital clock or internal memory that causes an intermittant draw?
    tb33anda3rd likes this.
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  5. Don't bother trouble shooting an electrical system with a battery that's not been tested and proven to be good. Don't assume it's ok, prove it is as it should be.
    Otherwise It will just be a frustrating, tail chasing, crazy making, infuriating, futile, exercise including inventing obscure and highly improbable scenarios to explain the symptoms.
  6. deathrowdave
    Joined: May 27, 2014
    Posts: 2,135

    from NKy

    Sounds to me like a voltage regulator issue

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  7. d2_willys
    Joined: Sep 8, 2007
    Posts: 4,094

    from Kansas

    It sounds weird alright! Well, the first thing is to find out where the pulse draw is coming from. Disconnect alternator, and if old voltage regulator is still hooked up then disconnect it too. See what happens. My guess is that one or both are the cause. If not, pull the horn relay plug. If still pulse draw, then another weird place is if the car still has original clock. If so find clock fuse and pull. If still pulse draw, then find anything else that is powered by the battery itself and disconnect.
  8. Barsteel
    Joined: Oct 15, 2008
    Posts: 726

    from Monroe, CT

    Thanks to all for their replies. I should have mentioned that the car no longer has a voltage regulator with the GM 1-wire in place.

    After I posted, I spent some more time with a test light checking lines, etc, and to make a long story short, I found that the pulsing draw stopped when I disconnected the "always hot" power line from the radio/cd player that the previous owner installed. Problem solved (or so I believe, time will tell).

    I do know that there is now NO power draw between the battery and the cable with ignition in the "off" position and the dome light fuse pulled, now that the always hot wire is no longer connected. The radio needs it to work, so I'm just going to pigtail both wires together and run it off of a switched terminal of the fuse box. I'll lose all my presets, but I guess I'll have to live with it.

    Question - could the car stereo be defective? I ask because all modern day cars have the same always hot connection to the stereo, and I've never had a problem with a dead battery on a newer car, even after the car has been sitting for a month. Yes, it works fine, but it's probably 10+ years old.

    Opinions? I have zero experience with car stereos.

  9. I would have to say that there's something wrong with the stereo. I suspect that the 'pulsing' was caused by an internal circuit breaker in the stereo opening/closing because of the extra load you put into the circuit with the test light (this is one reason I don't care for test lights). I'd replace the stereo....
  10. hvywrench
    Joined: Sep 29, 2011
    Posts: 158

    from N.W. Conn.

    If my memory serves correctly, there is a unit for the dash gauges that pulses voltage, but my guess is that it needs the key to be either 'on' or in 'acc' to be supplied voltage and pulse. It is a small rectangular metal unit bolted to the instrument panel. "IF" my memory is correct.
    EDIT: I looked at my shop manual for my '64 and the gizmo is called a constant voltage regulator and supplies pulsed voltage to the engine temp gauge and the fuel gauge. It should NOT have voltage with the key off. A quick check would be to see if either of these gauges work with the key off. If the fuel gauge reads fuel level, it is possible there is a wiring problem that is supplying that regulator with voltage, it will pulse between 3 and 10 volts.
    Also, there are two types of those 'Fuse Buddy' meters and inline fuse holders; ATC and ATM, the meter and the holder need to match.
    Whenever I have to try and trace a parasitic draw, I use a digital meter with a homemade inline fuse holder that has alligator clips on it instead of a test light.
    I can connect that between a removed battery cable and the post, then start unplugging items until I find with I'm looking for. I can measure very small amp draws with my setup. Test lights are a quick test, but I like to have values for the different loads. buddy fuse holder

    Newer cars have all sorts of stuff that needs constant power to keep the memory alive, I've found that about 1/4 amp draw with everything off seems to be the norm. Your memory for the stereo should be even less that that, unless there is a problem in the wiring or internally with the radio.
    Just my opinion.
    Last edited: Feb 12, 2015

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