Current Leak in electrical system

Discussion in 'General Motoring' started by Bill, Jan 10, 2006.

  1. Bill

    Bill Guest

    Something is draining my battery to the point where my 1987 Volvo 240
    goes dead. I had the battery loaded tested and proved good. I
    installed a new Bosch alternator thinking the current was leaking
    through alternator but the car battery still goes dead after 3 or 4
    days of sitting in the garage. If leave the battery cables
    disconnected, the battery is fine. Following are testing results with
    an amp meter:

    1. With the positive battery cable disconnected, at first positive
    contact between Positive on Battery and Cable with a Fluke Meter, we
    measure 200 mA.
    2. After two seconds, the amperage reading drops down and stabilizes at
    80 mA. We believe 20 mA of the 80 mA is the car clock.

    I suspect some type of electronic circuit board is charging up
    capacitors and then drops back to 80 mA.

    Does any one have any thoughts? Does anyone have a better strategy to
    diagnose current leakage?

    Bill - Philadelphia
    Bill, Jan 10, 2006
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  2. Bill

    JDG Guest

    I had a problem with my 93 850 like that. Turns out that I had put a CD
    changer in the glove box, and the light switch was not turning the glove
    box light off as it should. I didn't notice the light being on because
    the glove box was closed. The light was powered even with the ignition off.
    JDG, Jan 10, 2006
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  3. Bill

    D. Brown Guest

    Something is draining my battery to the point where my 1987 Volvo 240
    200mA isn't actually that much, so look for courtesy lights and things that
    are on. I'd be surprised if that was flattening your battery in a few days.
    You can try, with the multimeter installed, pulling fuses one at a time to
    try and narrow down which circuit the problem is in.

    Don't forget that if the radio has a memory that will draw a few mA as well,
    but I'd guess at no more than 10.
    D. Brown, Jan 10, 2006
  4. We had this same problem with our '89 240. It was a nuisance for several
    years. As long as you ran the car every day, it was fine, but if you let it
    sit for a couple of days, the battery went dead. I nailed it down by
    clipping the ammeter in series with the positive battery terminal (drawing
    about 240 mA), and pulling the fuses one at a time.

    In my case, it turned out to be a faulty door switch (to turn on the dome
    light). Remarkably, turning off the dome light manually did not fix the
    problem. I ended up removing the door switch (it was the right rear door,
    so nobody complained).

    Without the extra load of the faulty switch, just the clock and whatever is
    used to store radio presets, etc., the latent current draw is about 25 mA.
    Robert Lutwak, Jan 10, 2006
  5. Bill

    Mike F Guest

    I had one where it was the clock - the clock kept time perfectly, just
    took 100 mA to do it!

    Mike F.
    Thornhill (near Toronto), Ont.

    Replace tt with t (twice!) and remove parentheses to email me directly.
    (But I check the newsgroup more often than this email address.)
    Mike F, Jan 10, 2006
  6. I had the same problem twice with my 240 while living in L.A.
    I used to live on a steep street and when I just pulled in front of the
    house instead of the driveway, the angle of the street was enough to
    turn on the trunk light.
    The second time that it happened, it turned out to be corrosion on the
    connector that plugs into the ECM. Sprayed it with contact cleaner and
    hasn't happened since. Also, check the wires that come out of the
    firewall on the right side of the car. If the wires have deteriorated to
    the point where the insulation is flaking off, possibly they are
    touching and causing a drain.

    Good Luck
    .................................................., Jan 12, 2006
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