2003 Suburban battery draining

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by Sub Steve, Feb 3, 2012.

  1. Sub Steve

    Sub Steve New Member

    The battery on my 2003 Suburban keeps being drained. I charge it up to 12+ volts and overnight it drains to about 5-6 volts. I believe I have ruled out a bad battery as I have switched it with another vehicle and the problem stays with the Sub. I removed the wire that attaches to the alternator and the problem doesn't go away so I think it isn't the alternator, plus the battery reads at about 14.75 when the Sub is running so the alternator seems like it is doing its job??

    What else would be draining the battery that fast? What else do I check and how?
  2. Sub Steve

    Sub Steve New Member

    Today I unhooked the negative battery terminal and put my multimeter inline between the negative cable and the negative post. I tried using the millivolt setting, but it gave the OL error message, so I used the regular setting. The multimeter read 12.89. That means it is a much larger draw than just a dome light or something little like that, right? What are the larger items that would be drawing that much current when the vehicle isn't running?
  3. Dana W

    Dana W Rockstar 3 Years 500 Posts

    I had a similar problem in a 1999 Sub I just bought. The prior owner blamed "all the computer stuff".

    I discovered a broken hinge on both of the vanity mirror covers. The broken hinges caused the cover to exert too little force on the tiny plunger switch that turns the mirror lights on and off. Since the plunger switch was not depressed far enough, the lights stayed on all the time. The lights could not be seen even in the dark with the mirror cover closed and the visor in the full stow position. This doesn't seem like a lot of drain but those 4 tiny bulbs would drain the battery too low to kick on the starter solenoid in one night. Apparently the bulbs don't come out of the sockets, and I could not find a connector inside the visors so I had to cut the wires.

    I can start the truck every morning now, so that's better, but I need new sun visors. I also broke one of the plastic frames getting them off.
  4. Treadnmud

    Treadnmud New Member

    At 14.75 volts that is actually a little high. A discharged battery that is still good will read around 11.6 volts. Any less than that the battery is trash.

    You can also hook you ammeter up in series with the battery cable and start pulling fuses one by one and checkin the amp draw, you are most likely looking for a draw on the battery side of the fuse panel and not the switched accessories. Hope this helps.
  5. Sub Steve

    Sub Steve New Member

    Today I hooked up the multimeter inline with the battery again. I think I was using the wrong setting previously. I have the negative battery cable disconnected. I put the red end of the multimeter on the negative battery cable and the black end of the multimeter on the negative battery post. I turned the multimeter to mA and it read .9

    From there I pulled every fuse under the hood, every fuse from the compartment just inside the drivers door and every fuse from the compartment just to the left of the brake pedal. Nothing changed. Then I disconnected the wire from the started and that too changed nothing. The multimeter still read .9 mA.

    What's next?
  6. Treadnmud

    Treadnmud New Member

    .9 mA is a very small amp draw. That would be just under 1 amp. I don't think that is your problem. You do have have constant power to things like the radio but you pulled the fuses. Hmm. There are also two wires coming off the hot side of the battery, one to the starter and one to the fuse panels.
  7. Naptime

    Naptime Rockstar 100 Posts

    I'll share. I had a similar drain. It really is a very common issue. 90% of the time it is a broken hinge on a vanity mirror, an interior light left on, or the under hood light. So check it out after dark. I had a broken hinge. I now keep a small square of foam rubber wedged to keep it closed.

    After you rule that out, it's time to check things like an after market alarm. I removed the antiquated Clifford and pitched it, then started pulling fuses.
    Nothing remarkable there. Similar to your small drain.

    I still had a drain that would necessitate hooking up an overnight trickle charger every couple of weeks.

    Then it started getting to be where it didn't want to start after short trips. I'm thinking starter. Took it out, had it tested, and it checked out fine.
    Since I had it out, and it appeared to be OEM, I bought a new one.

    That was months ago, and I haven't had any "battery" issues since.

  8. ahm1127

    ahm1127 Rockstar 100 Posts

    My switch for the rear window defrost was broken & couldnt shut it off. Would drain my battery overnight.
  9. Sub Steve

    Sub Steve New Member

    OK, I think I’m a little further along since I borrowed some equipment from a neighbor. I hooked up his ammeter in series and discovered that my draw is 19ma. The strange about this is that it doesn’t appear to be a steady 19ma draw. The ammeter goes into overload then drops back down to 19ma consistently, over and over. We had it hooked up for over an hour and it repeated that process throughout the entire hour.​
    We started pulling fuses and the problem went away when we pulled the MBEC fuse. The manual says the MBEC fuse is related to Mid Bussed Electrical Center Power Feed, Front Seats, Right doors.​
    How do I figure out which of these items is causing the problem?​
  10. Kapelusprime

    Kapelusprime Member

    I'd start with the door, the amount of water from condensation and the elements can corrode and short door switches, window switches, window motor. Then look for draw in the power seat at the switch and the motor. Continuity at the ground side of a switch or motor, to a ground such as bare metal will be a tell tail.

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