Electrical drain/leak, but very very acute

Tiny
TSHUMP18
  • MEMBER
  • 2008 HYUNDAI ELANTRA
  • 2WD
  • AUTOMATIC
  • 110,000 MILES
So, I have had other posts regarding this car. But will start anew on this.

I have bought a bunch of batteries recently as I was thinking things were different each time. The first time I thought it was just a lemon of a battery. Then the second I started to think it was something else, however, I charged it one too many times I believe and burned it out. That's what the shop said at least. And then on to my current one same issue.

The shop said "cannot find a parasitic drain or leak anywhere, must be a dead battery from charges." They did replace the door jam light switch as they thought was the source and then said, again, cannot find a drain. Figured all was well and that's when I got the current battery. Well, after 2 weeks on the dot of getting it and putting it in, it died again. I have a charger so I changed it. Now going on 5 days on that charge.

So, in the end, whatever it is, the leak is very, very slow. Maybe undetectable with conventional testing tools? I also replaced the positive battery terminal connector on it because the old was worn and corroded. Would that have any bearing on things?
My question really is, any off hand suggestions as to what you think it could be? Again, I have a charger and have a portable jumper, so I have a stop gap in the interim until I can get it to another shop and really figure out what the hell is going on.
Tuesday, January 7th, 2020 AT 10:04 AM

11 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Often times, when it is this slow at draining, it is related to a small bulb at some point such as a trunk, mirror, glove box light and so on. First, take a look through this link and see if anything helps:

https://www.2carpros.com/articles/car-battery-dead-overnight

I will assume that the alternator was also tested, but it could be weak enough to allow this to happen. I'm not sure where you are located, but if you are running the heater, lights, and other electrical components, it could be enough to cause a problem.

Here is a link that explains how to test an alternator. It is very simple and all that is needed is a multi meter or volt meter.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Here are a couple links you may find helpful when testing:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

Let me know if any of this helps or if you have other questions.

Take care,

Joe
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Tuesday, January 7th, 2020 AT 9:25 PM
Tiny
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As you can tell, it's been a while. :) I've been doing a work around to get through the winter. Darned cold here in Minnesota and no heated garage! I charged the battery and then just remove the terminal hook ups when parked for extended periods of time and the obviously hooked them back up when driving. Works, but is tedious, especially when it's -10 degrees outside. Now it's getting close to spring and time to tackle this bastard again.

I want to do the power drain/leak test myself. I have a voltmeter with test light and have read the instructions in the links. However, I think I am confusing myself. What is the best way to do it in your opinion? I want to hook up the test light and then start pulling fuses to see if I can pinpoint. How shall I hook it up? Use a ground and then just pin the needle of the test light into the positive terminal?
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Friday, March 6th, 2020 AT 10:01 AM
Tiny
JACOBANDNICKOLAS
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Hi,

You will need to use a volt meter or multi meter because there will always be some draw on the battery which will keep the light on.

So, take a look through this and let me know if it makes sense. If you have any questions, let me know.

______________________________________________

If you can't find the cause of the battery drain, a manual draw check of the electrical system will need to be performed. With the ignition key in the off position and the doors closed (driver's side window down) disconnect the battery cable on the negative side. Then take you voltmeter and set it on the DC amp scale. Then attach the red lead to the battery post, negative. Take the black lead and attach it to the battery cable. Use a small jumper wire along side of the voltmeter and wait for 15 minutes to allow the modules to go to sleep. Then remove the small jumper wire leaving just the voltmeter. Then look at your reading, it should be about 50 to 75 milliamps. That is considered a normal draw to keep the modules backup systems charged.

If the draw is higher than that, then start removing the fuses one by one until the draw drops to the normal levels. Once you find the fuse, you will need to look for a power disputation wiring diagram that will show what components are on that fuse. Install the fuse and go to each component on that circuit and disconnect the components one at a time until the draw drops to normal range. At this point, you have found the draw. Replace the component and recheck the draw to confirm your repair.

_________________________________________________

Let me know if you need help.

Take care,
Joe
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Friday, March 6th, 2020 AT 10:32 PM
Tiny
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Been a really long time now :) Since the COVID outbreak this car has mainly been relegated to sitting in the driveway. However, now I want to give it some TLC. So, I did a draw test on this and it's getting a very very acute draw. Just 0.16 milliamps. But we want it between 0.02 to 0.05, correct? So, not a huge draw, but enough to kill it after a few days, week or week and a half to 2 weeks.

Now, I pinpointed the fuse as well. It's the ROOM LP fuse (again, 2008 Hyundai Elantra) and I see five things on that. Map Lamp, Dome Lamp, Trunk Room Lamp, digital clock and Home Link. Now, wasn't sure what the hell the home link is but did a little research and pretty sure this car doesn't have that :) I've read the ROOM LP can be pretty dreaded when it comes to draws, so I am wondering if there is more than meets the eye than just the 5 things going to it.

So with that, I hooked up the multi-meter again and got the draw and started taking those components apart (door shot, car off and "sleeping") to see if just unplugging the components would do the trick one-by-one. Would that work, just unplugging them? Because it didn't for me. Or do you have to clip the wiring to whichever is causing the issue? That's the part I am trying to avoid :) Not sure if I am going to want to go behind the fuse box and pinpoint the exact wire.

Any other suggestions you can think of, I am all ears. Right now, instead of disconnecting the battery all the time, now I just pull that fuse when the car is going to be sitting for an extended period of time and/or over night.

Talk soon.
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Monday, June 22nd, 2020 AT 3:24 PM
Tiny
JACOBANDNICKOLAS
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Okay, the fuse you found as the draw basically covers everything you mentioned. Do not cut the wires to test for a draw. How did you check the trunk light? Did you remove the bulb? Where were the other components disconnected?

If you look at the two pics below, I attached the entire wiring schematic for that circuit. See if anything was missed.

I cut the pic into two parts so you could read it. However, I did overlap them so you could follow from one to the other.

Joe
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Monday, June 22nd, 2020 AT 10:08 PM
Tiny
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No, I am not cutting any wire, I was going to do that as a last resort and/or remedy as the car is old and has 110,000 miles on it. I wanted to pinpoint the wire if I can and then cut it to remove the draw. I don't know if I'd have the wire fixed or not, especially if it's something simple as a dome light or trunk light, I don't care if those don't work. :)

But what I did with the digital clock, trunk lamp, map lamp and dome lamp was simply unplug them. I popped the plate open on the dashboard to get to the back of the digital clock and literally just unplugged it from the unit. Did the same for the other things as well. Didn't remove any bulbs. Basically what you would do if you got a replacement part. Unplug the old and simply plug the new in, and pop or screw it back into place.

I was hoping that's all it would need to be done so I don't have to clip any wires to fix anything. But would simply unplugging like that do the trick? If so, then I need to unplug elsewhere since I unplugged all of them and that didn't do it.

I am wire diagram illiterate I'd say. I'm trying to make sense of it.
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Tuesday, June 23rd, 2020 AT 9:31 AM
Tiny
JACOBANDNICKOLAS
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What you did makes sense. However, I want you to tr something different. Unplug all of the components at the same time to see if the draw is gone. If it is, then plug one in at a time until the draw returns.

I know that sounds like the same thing just in reverse, but there could be something you disconnected that has a short and is allowing power to be drawn all the time. If everything from that circuit is disconnected and we still have a draw, then we need to start checking the wiring between the fuse and components for a short.

Also, there could be one power wire that supplies power for a few different things.

Does that make sense? Let me know if you have questions,
Joe
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Tuesday, June 23rd, 2020 AT 7:42 PM
Tiny
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Well my friend, I figured out where the draw came from! I was kind of doing what you suggested already. Just unplugging things all at once and one-by-one plug them back in, etc. Got nothing. Unplugged a few other components for the heck of it to see and got nothing. Was about to throw my hands up and say "well, gotta go to the shop, can't figure it out." Then thought at the last moment as I was putting all the door jam switches back into place "hmm, let's do the driver side front door, that had work on it." Bam, removed the door panel and unplugged everything there, boom, draw went to 0.00 and fluctuated between that and 0.01. :) Yay! Then plugged in each door component one-by-one to find the culprit and found it. Was the wiring going to the outside door mirror. I plugged that in. Draw went up to 0.16, unplugged, down to 0.00. Just leaving it unplugged for now as it really isn't vital to me. Maybe at some point I'll get it taken care of either by myself or a shop, but we will see, just glad I found where it was.

Thanks for everything. Your opinions and suggestion helped push me over the edge to find this pesky problem.
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Wednesday, June 24th, 2020 AT 7:34 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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You are very welcome. I'm glad you got it figured out. Electrical issues can be a pain. Regardless, please feel free to come back anytime you have questions. And by the way, thanks for letting me know what you found. I wanted to know and I'm sure your resolve will help someone in the future.

Take care,
Joe
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Wednesday, June 24th, 2020 AT 9:59 PM
Tiny
TSHUMP18
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Yes, electrical issues with vehicles is a complete headache. I will say, this has been a one stop shop for pointers and I appreciate that. Helps to have another head in the game to find anything under the sheets I may have missed.

Thanks again, and I'll be sure to reach out with any further questions. :)
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Thursday, June 25th, 2020 AT 7:27 AM
Tiny
JACOBANDNICKOLAS
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Happy I was able to help.

Take care,
Joe
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Thursday, June 25th, 2020 AT 8:52 PM

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