1998 Jimmy SLT. Battery drain.

Discussion in 'Chevy Blazer Forum (GMC Jimmy)' started by LUVMYJIMMY, Dec 16, 2016.


    LUVMYJIMMY New Member

    Old problem. It has done this since purchased in 1998. Sitting in driveway results in battery undervolt after a couple of days. Turns the engine, but temporary drop to less than 12.5 volts keeps the fuel pump (replaced) from generating enough pressure. Has anyone ever sourced the drain on these vehicles?

    4.3 V6 Vortec, auto, 2 wheel drive, PW, PS, PB.

    totally unrelated comment...the fuse for the gas gauge is labelled "4WD" on the fuse compartment lid! I have the 2WD truck.
  2. thegawd

    thegawd Rockstar 2 Years 1000 Posts

    well they must have used the wrong sticker! LOL

    I would check to make sure the passanger side visor vanity lights are going off as they should when the mirror is closed. the lid may need a slight adjustment to properly contact the off switch. I had this problem on my old 94 burb and it took 2 years and a reason to get something out of the glovebox in the middle of the night before I found it, coincidentally the visor was down. you cant see the light from the drivers seat.

    id also check the glove box light and make sure the undehood light is going off when the hood is closed. I had to bend the bracket on my old 94 to make it go off right, but this wasnt the only problem cuz i hadnt found the visor yet...
    RayVoy likes this.

    LUVMYJIMMY New Member

    Thank you! I checked all of them out, found one vanity light not working at all...bad switch...fixed. I have installed a battery disconnect, but it is a pain. So I mounted a solar maintainer for the short term on the dash. Make sure ALL available switches and knobs are off upon exit. The search continues...
    thegawd likes this.
  4. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Hmmm, a fully charged battery (lead acid) should read 13.2 to 13.4 volts.

    A voltage of 12.5 is not charged, but sure not discharged.

    Are you saying a voltage of 12.5 volts won't operate your fuel pump (enough to give you pressure)?

    Very strange, I would think a fuel pump would be happy with 10 volts. We start trucks in the sub zero temps all the time.

    I'd take a look at the pressure requlator,

    or the wiring to the pump. Maybe the ground is poor, giving you a voltage drop.

    LUVMYJIMMY New Member

    Thanks for the suggestions. I got the 10 volt info from a YouTube video by a mechanic at a training center giving instruction on what to check if a fuel pump problem is occurring. I checked his advice and saw that my voltmeter dropped to just over 9 volts during cranking. This difficulty in starting usually occurs after the truck has been sitting for more than a day, so I still suspect a drain somewhere...I have checked the courtesy lights and accessories, they do not remain on. The ciggy lighter does blow fuses pretty easily, so that is my next target...maybe an occasional short...
  6. thegawd

    thegawd Rockstar 2 Years 1000 Posts

    I think your getting closer to finding it. its possible to have a short that dosent blow a fuse all the time because the current is to low. but once you plug somethng in that draws more current is when it then blows the fuse.

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