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07-10 2500hd electrical issue? anybody else?

Discussion in 'Chevy Trucks' started by Droozy, Sep 19, 2014.

  1. Droozy

    Droozy Junior Member
    Messages: 7

    So my 08 GMC 2500 hd has this weird electrical draw, where as if I don't start the truck for 3 days or more... its completely dead. I have the snow option from the factory, and it will drain both batteries.

    Took it to my mechanic... nothing. cant find a single issue because it doesn't have a constant drain. randomly will pull juice.

    took it to the dealer.... Nothing. Same thing as the mechanic, no draw at the time of testing. They did say if anything comes across the service bulletins, they will contact me.

    things Ive done to see if it helps:

    Unhooked plow solenoid from battery... nothing
    unhooked " " and trailer wiring harness.... Nothing
    Unhooked every god damn thing from aux battery.... nothing

    Just seeing if anyone here has had any issues like this, or even better what I can look at to find a draw as its more power then a simple water drip on a electrical connection I think. And add 1 more person to the list... Customer of mine has a 09 Silverado... does the same thing... 2500 hd, not used for plowing... dead after 3-4 days of no use.
  2. jerzeyguy

    jerzeyguy Junior Member
    from 07080
    Messages: 15

    I had a similar issue on 08 gmc 1500 no plow
    Or aftermarket equipment, it was the light in
    The glove box causing the issue.
  3. Droozy

    Droozy Junior Member
    Messages: 7

    Wouldn't that show a draw all the time though?
  4. rjigto4oje

    rjigto4oje PlowSite.com Addict
    Messages: 1,380

    Yes it would show a draw all the time, does your have a draw all the time, many things can cause draws we have all seen weird things give us some history on the truck
  5. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,391

    Just double cking, has the places preformed a parasitic draw test?
    And the glove box could be plausible, pull the light out
  6. rjigto4oje

    rjigto4oje PlowSite.com Addict
    Messages: 1,380

    Just Googled your problem everything from bad batteries to wiring issues to bsttery cables if you can get an amp meter and hook it up between the battery and the negative cable some techs use a test light either way if the meter shows anything more than .02 to .04 you have a draw start isolating by pulling fuses till the draw goes away
  7. DaBomb6988

    DaBomb6988 Member
    Messages: 64

    With the snow plow prep there should be a switch in the upper console for a beacon light. It isn't on is it? I had the same problem and turned out to be that switch was on.
  8. If the light on the switch in the overhead console is on the relay above it is powered, drawing power even if nothing is hooked up to the wiring harness that is coiled up above the console. Prior to 2011 model year GM spent a lot of money on " no start" bumper to bumper warranty claims when someone unknowingly brushed the switch on accidently. From fall 2010 you have to plug in the relay to use the beacon lamp switch----easy fix. There is a TSB about this.
  9. jerzeyguy

    jerzeyguy Junior Member
    from 07080
    Messages: 15

    It was very little almost unnoticeable but it showed over a couple of hours, I was told by the mechanic
    Or it was dumb luck that he found it.
    I'll never know.
  10. Whiffyspark

    Whiffyspark 2000 Club Member
    from SOMD
    Messages: 2,403

    Don't use a test light unless it has an actual bulb in it. I just a old style bulb for dome lights.

    Put it in between negative terminal and negative cable. And start pulling fuses one by one.

    I'll use an amp meter sometime, but usually prefer the bulb
  11. SnoFarmer

    SnoFarmer PlowSite Fanatic
    from N,E. MN
    Messages: 9,883

    Id use a VOLT meter instead of some light bulb or a amp meter.
    but the light is what ya will use if you don't have a meter.

    one to two volts of parasitic loss isn't going to light up your bulb.
    will, if your in the dark it might work....
  12. Whiffyspark

    Whiffyspark 2000 Club Member
    from SOMD
    Messages: 2,403

    Like I said needs to be old style bulb.

    You don't check for a draw in volts either. 1 volt would have the bulb bright as hell.
  13. SnoFarmer

    SnoFarmer PlowSite Fanatic
    from N,E. MN
    Messages: 9,883

    Your bulb shows nether amp or volt just that there is some sort of a draw.

    Before parasitic draw testing it was the tried and true old test light method between the battery post and cable. It was accurate enough, it wasn’t precise as far as voltage or amperage but, it got the job done. If the test light was even partially lit up… hey, there’s a draw. I never worried about the actual amount, it wasn’t important, only the “where is it” was. So how about a way to locate these draws in a modern car and not worry so much about the exact values… just find the problem and leave all that technical mumbo-jumbo aside. There is a way, and all it takes is your volt meter.

    Start with a good multi-meter (DVOM) with an mV scale (milli volts) and a couple of good test leads with sharp pointed ends. Put the meter on the milli volt scale and your test leads on the two test points on the back of the suspected fuse and measure the voltage. Yes, that's right... the negative lead from your meter on one of the fuse test terminals and the positive lead on the other. (On some fuses these little test spots on top of the fuses are quite small, this is where the sharpened points of the test leads will help out.).

    A good practice session for this method is to try this on a car that is working. Find the dome light fuse and watch the meter. If there is no current flow across the fuse the meter will read a flat zero. If there is a current flow in the fuse you will measure a steady voltage drop of some sort from the time the door is opened to the time the dome light finally goes off, it doesn't matter what the voltage is, just that it is there.

    The reason this works is that all circuits have some resistance in them. This resistance to current flow causes a minute change in the voltage readings from the source to the load itself. Current flow also creates heat, heat increases resistance and current flow through this resistance is seen on your meter as a voltage drop. Any voltage measured across the fuse then indicates some current flow. If you get a small fluctuating voltage you’re probably not on the fuse test points. This is where those sharp test probes really help out again. There should be either no voltage at all, or some sustained voltage level that will be constant. Just like any other testing method practice makes perfect, and trying this out on a car with no problems is a good way to see how this whole thing works.

    I like this method and prefer this to the amp meter testing method. I’m not disconnecting anything, I’m still looking at a voltage drop (not amperage) and I’m less likely to screw up another amp fuse in my meter. I’ve even had success with this by starting at the MAXI fuse, then following the wiring diagram to break it down even further until I found the source of the draw. The only time I start pulling fuses is after I’ve got the draw isolated to one section of the wiring diagram or fuse box. I’m not concerned so much with accurate values or amperage loads, just where the draw is coming from. The fact that I’m seeing voltage on the meter in a circuit that shouldn’t have any current movement is enough information for me to suspect that this circuit is the culprit.

    This is as close to using the old test light method as I’ve ever found. Mind you, the reason the test light worked at all is because of the same reasons this test works. The presence of any load requires both positive and negative to create current flow. Thus, the reason your test light lit at all.

    have fun
    Last edited: Sep 24, 2014
  14. Droozy

    Droozy Junior Member
    Messages: 7

    My head is spinning... lol But im going to give the volt meter a go tomorrow. wish me luck
  15. RichG53

    RichG53 PlowSite.com Addict
    Messages: 1,135

    Drank two cups of coffee reading that one..