How to locate what is draining the truck battery?

Discussion in 'Shop Talk' started by snoozy, Jul 22, 2005.

  1. snoozy

    snoozy Well-Known Member Supporter

    Messages:
    3,025
    Joined:
    May 10, 2002
    Location:
    Kitsap Co, WA
    Okay, I have a 1983 Diesel Isuzu Pup in fine shape. However, something has been draining the battery. It could be the generator is not generating like it oughter, but if I unhook the battery when I park the truck for any length of time (e few hours, overnight), then the battery is fine and is not even weak. So this is why I am thinking that something may be drawing electricity from the battery even while the truck is off. When I rehook-up the battery, by the way, some dohickey on the right side of the engine clicks, but I don't know exactly what the dohickey is or if it is normal that this click "on" should happen.

    How do I take one of these voltmeter/ampmeter thingees and find where electricity is flowing when the truck is off but the battery is connected?
     
  2. marvella

    marvella Well-Known Member

    Messages:
    4,910
    Joined:
    Oct 12, 2003
    Location:
    tn
    i had the same problem a few years back. the light in the trunk was staying on all the time. also check the glove box.
     

  3. rzrubek

    rzrubek Flying Z

    Messages:
    648
    Joined:
    May 12, 2004
    Location:
    Chapel Hill, NC
    Can you post a pic of the doohickey? Kinda sounds like the airconditioning idle increasing selonoid that gas engines have. Not familiar with diesels though.
     
  4. fordy

    fordy Well-Known Member

    Messages:
    9,333
    Joined:
    Sep 13, 2003
    Location:
    Whiskey Flats(Ft. Worth) , Tx
    ...................Snoozy , go buy yourself a Good 12vdc Test lite. Now , remove the minus terminal on the Battery and insert the testlite betwixt the cable and the minus on the battery terminal . Start pulling fuses , and when the test light goes OUT.....you've found the circuit with the "drain" . From there on it's just a matter finding the particular item that is creating the problem . ..fordy.. :goodjob:
     
  5. John Hill

    John Hill Grand Master

    Messages:
    491
    Joined:
    May 12, 2002
    Location:
    New Zealand
    It is the doohicky every time!

    Seriously, as far as I can deduce connecting the battery when everything is turned off should not cause any doohickies to make any noise.
    The problem might not be with the doohicky itself as it might be controlled by something else. However as suggested by rzrubek post a picture or description so that someone might be able to guess at what it is which may lead to finding the cause.
     
  6. snoozy

    snoozy Well-Known Member Supporter

    Messages:
    3,025
    Joined:
    May 10, 2002
    Location:
    Kitsap Co, WA
    And all this time I thought that dohickey was a technical term...

    Here are pictures of said dohickey:
    [​IMG]
    [​IMG]

    Fordy -- That was just the directions I need. I'll be borrowing such a metercritter tomorrow and see if I can follow them!
     
  7. snoozy

    snoozy Well-Known Member Supporter

    Messages:
    3,025
    Joined:
    May 10, 2002
    Location:
    Kitsap Co, WA
    Yikes! That came out HUGE :eek: !
     
  8. Cabin Fever

    Cabin Fever Life NRA Member since 1976 Supporter

    Messages:
    15,597
    Joined:
    May 10, 2002
    Location:
    Between Crosslake and Emily Minnesota
    Ya know, that's exactly what my wife......ah forget it, I don't what to get kicked off the forum.

    Good luck with your huge dohicky problem.

    See ya....
     
  9. snoozy

    snoozy Well-Known Member Supporter

    Messages:
    3,025
    Joined:
    May 10, 2002
    Location:
    Kitsap Co, WA
    Cabin -- The technical term for what you're alluding to is a Thing o'myBob. (If his name is Robert...) ;)
     
  10. John Hill

    John Hill Grand Master

    Messages:
    491
    Joined:
    May 12, 2002
    Location:
    New Zealand
    Okay, those look like two regular doohickies disguised as relays.

    Usually they are devices that are used to control a large electrical current by means of a little current. Usually they can be unplugged and these particular 'hickies look like they have caps to pull off.

    If it were me I would try to identify what the intended function is, they will control something for example electric radiator fans or the air con clutch. If there is nothing written on them pull one one and put the battery back in then check the vehicle to see what has stopped working!
     
  11. Cosmic

    Cosmic Well-Known Member

    Messages:
    596
    Joined:
    Jan 19, 2005
    Location:
    Ohio
    One easy thing to try is turn off all switches first.

    One of my neighbors bought a new car and the battery kept being drained. Turned out to be some stupid Gizmo switch was being left on. Many cars are loaded with them, this one was some light on the dashboard. Can be a light saying a door or whatever is not fully closed. Check the obvious first. The fact the switch is on and there can be some sort of circuit leakage, like a windshield wiper switch, even if the device can't get enough juice to operate. Can be a strange set of facts that is not always techically sensible. Including turning off the radio, etc.

    Maybe you have turned something on and don't realize it. One clue is it is probably a very light load, like a very small light bulb or LED display. Usually if it is any load of any size, your battery don't survive the drain downs very long, just a few totally dead cycles kills it.

    Lots of things can get a fellow in this life. Doo-hickies, Thing-a-ma-jigs, Gizmos, Discombobulators, Round-2-its, the list is just about endless.
     
  12. fordy

    fordy Well-Known Member

    Messages:
    9,333
    Joined:
    Sep 13, 2003
    Location:
    Whiskey Flats(Ft. Worth) , Tx
    ..................Snoozy , that item in the picture looks like some kind of pressure sensing device as it appears to be tied into the braking system . Looks like you have a Pair that also are utilizing those black vaccum lines to control or activate a function of maybe the ABS system if your vehicle gas such . fordy.. :)
     
  13. agmantoo

    agmantoo agmantoo Supporter

    Messages:
    10,855
    Joined:
    May 22, 2003
    Location:
    Zone 7
    Fordy, look at both pics again. I think the device is just a relay. Looking underneath the blue one you will see 3 or 4 wires coming out of a harness. The area is rather cramped and from the pic it is difficult to make a correct call. I haven't a clue as to the relays function but I am surprised that it would click with the doors closed, lights off , and the ignition key removed.
     
  14. Ross

    Ross Moderator Staff Member Supporter

    Messages:
    13,086
    Joined:
    May 9, 2002
    Location:
    Ontario
    Yeah its a relay and you'd need a schematic to tell exactly what it does but two guesses, fuel pump could be one and as its a diesel it could be the preheater relay. If its clicking on your peheat (assuming it has one and I'd bet lunch it does) your battery will die fast.
     
  15. fordy

    fordy Well-Known Member

    Messages:
    9,333
    Joined:
    Sep 13, 2003
    Location:
    Whiskey Flats(Ft. Worth) , Tx
    ...................Yep , it looked like it was tied into the brakes but probably Not . Ross , is guessing correctly , I'm guessing :bow: :eek: :rock: and 1983 is Too early for anykind of ABS system now that I think about it . fordy.. :help: :nerd:
     
  16. snoozy

    snoozy Well-Known Member Supporter

    Messages:
    3,025
    Joined:
    May 10, 2002
    Location:
    Kitsap Co, WA
    The battery does die fast if I don't unhook it, but as long as the truck is running, it seems okay. If it is the preheat (you mean the glow plug, yes?) , do you think the said dohickies pictured are the problem and the fix would be to replace them? (If they are indeed the culprits?)

    When this problem was building up -- it started some months ago and only became dire last week -- the battery light would go on as well as the "Fuel filter needs draining" light when I came to a stoplight, and the engine would make pitiful complaints, but if I gave it some gas, then the warning lights went out, leading me to think maybe I needed to raise the idle. But of course, I never got a Round-to-it (speak of the devil...) Then last week, for no apparent reason, one morning the battery was dead as a doornail, and took quite a long jump to resussitate. (The battery is only one year old.) I have since charged the battery with one of those rechargerdudes, and figured out the trick of unhooking the battery, and the warning lights and pitiful snuffles don't happen anymore. But of course, this is no way to live....
     
  17. mohillbilly

    mohillbilly Well-Known Member

    Messages:
    141
    Joined:
    Mar 24, 2005
    Location:
    south west Mo
    I have an 84 ranger diesel. had glow plug issues in the past. the problem sounds like a glow plug issue. some diesels use what is called after glow. when the engine is not fully up to temp, the glow plugs will cycle off and on at a reduced voltage to maintain proper fuel ignition.I would check something other than the relay. if the battery is going dead, and the relay clicks off and on when the battery is connected and disconnected, the relay is probaly fine. What triggers the relay is the issue. Check coolant sensors and the associated wiring. If a sensor switch is stuck , making the thing think it is always cold, even with the en=gine off, it will cause current draw and kill the battery. Also do as otheres have posted and pull fuses with a test light in line with the disconnected negative terminal.


    i bypassed all the factory sensors and made my glow plugs operate manually with a simple toggle switch in the dash that controlled the glow plug relay. Be careful if this is done, turn them on too long and you WILL fry the glow plugs.
     
  18. John Hill

    John Hill Grand Master

    Messages:
    491
    Joined:
    May 12, 2002
    Location:
    New Zealand
    I think Mohillbilly is right, it is not the dohicky relay that is at fault but the umgrummit that controls the dohicky relay. This could be as suggested a temperature sensing switch that controlls the glow plugs or it could be another temperature sensor that controls the radiator electric fan but as you didnt mention the fan running all the times maybe not.

    However, even if those umgrummits are faulty they would not be able to get to play unless they were being supplied with power and I suspect such things as the radiator fan, the glow plugs, the fuel pump or anything else would not normally come into play until the key is in the 'start', 'run' or at least 'on/acc' position. The same goes for any other switches that may control such dohickies, the advice to double check every thing is turned off is good advice.

    I suspect the key switch. Key switches are among the most mischevious of all umgrummits and dohickies because they are subject to mechanical disturbance every time you start the vehicle and more particulary because they are expensive.

    The battery light coming on indicates that electrical circuits were taking more power than the alternator was producing at that engine speed which maybe because the glow plugs have been alive all the time and continue to suck ergs even when the engine is running. I dont know how the drain filter bowl sensor works but if it works by monitoring something it might be getting confused by the glow plugs being on though that is a very wide guess on my part.

    Precis, subject the 'ignition' switch to intense scrutiny and look for any lash up that any previous owners have made in that area. My suggestion anyway.
     
  19. Cosmic

    Cosmic Well-Known Member

    Messages:
    596
    Joined:
    Jan 19, 2005
    Location:
    Ohio
    Yup, you should be able to isolate your problem into two parts.

    1. Those things that need power via the ignition switch to work or have power applied to them at all.

    2. Those things that do not need power via the ignition switch to have power applied. This should be a fairly small number and will vary with the age / make and model of the vehicle. Examples headlights, horn, cigarette lighter in many cars.

    Your problem is compounded a bit because you probably don't have the book that every fixing type should have for every vehicle they own. Guessing or looking is a poor substitute for being able to look at a electrical schematic. You can go nuts without a schematic and fix it quick with one.

    Back to the problem:

    If the ignition switch is supplying the mystery load that is draining the battery it can be isolated by disconnecting the connector that supplies power to the ignition switch and steering column. Should be down close to the floor to the left hand side of the footwell for the driver. If you disconnect this connector and the battery doesn't drain down, that tells you the mystery load in question is being supplied via the ignition key or something on the column. Does not neccessarily say the ignition switch is bad. In some cars power is available on the column to certain loads without being routed throught the ignition key, in others all loads go thru the ignition key. Is why the service manual / schematic is so important.

    There is one wire in the bundle going up to the steering column that supplies +12 VDC. That is how most folks put a kill switch in the car. They open that connector, on the hood side of the connector find the pin with the +12 VDC and put a switch in series in that wire. You cut it, splice in and wire out a kill switch which is hidden. If the test shows, your problem is being supplied via the steering column / ignition switch power source that can be one practical solution, even if you never find the problem. Plus you have one of the best anti-theft devices around. Turning off that switch effective isolates power. Basically makes it easy to do on a daily basis, without monkeying with the battery cables to turn off power in the car. I install kill switches on my vehicles, is a must have in some areas. On a Dodge Colt, a kill switch does not totally isolate power to the entire steering column. On most older cars it probably does.

    If you problem is not in the power going to the steering column then the problem is more difficult. You have to find the offending critter and either replace it or add a switch in series with it. If the offending critter is super expensive and maybe not worth the expense, a cheap isolation switch wired to an easy to use area can be a solution.

    First I would isolate the problem to power being supplied via the ignition switch / steering column or not type test by disconnecting that connector for a period and seeing what the results are. Then figuring out what possible solutions can be. You do not always have to find the offending critter.
     
  20. snoozy

    snoozy Well-Known Member Supporter

    Messages:
    3,025
    Joined:
    May 10, 2002
    Location:
    Kitsap Co, WA

    I had no idea that on the Shop Talk Forum there was such spicy talk as "after glow" -- I'd've visited this forum much sooner just for the thrill... :sing:

    Ahem...how does one tell if a sensor switch is stuck?