At a loss - Parasitic Draw on Battery (mechanics baffled))

[Smitty114]

I have a 2007 4runner that i bought in 2010, has about 140K miles and I was planning to drive it to at least 300k.

In the last 6 months something has begun to draw against the battery when the car is off. I've replaced the alternator and gone through 3 new batteries. I've taken the car to my local Toyota specialist, and now have taken it to the Toyota Dealer. Both have determined there is a draw, but can't figure out what it is. They went through the process of testing each fuse 1 by 1 and still can't figure it out. The first place said the only fuse they couldn't test was the one in the theft deterrent system, but that it's about 20+ hours of labor just to GET to it to test. Apparently it's buried deep within the vehicle. They couldn't guarantee that would fix it, although they said it basically couldn't be anything else. So, obviously I didn't want to commit $2000+ on something they couldn't guarantee.

I do have an aftermarket radio that was installed about 2 years ago. But never had any problems with the battery until the last 6 months. Since aftermarket items can often be the cause of a battery drain, we obviously tested this first. We completely disconnected the radio and removed it's fuse and there is still battery drain even when it's not connected, so it's obviously not the culprit as verified by 3 different places.

The car needs to be jumped if i don't drive it within 48 hours, every time.

Does anyone have any ideas or recommendations?

I'm almost to the point where I'm going to have to just buy a new car, which sounds ridiculous!


EDIT: Recommended solutions so far are to buy a battery charger for the days I'm not driving it, which means i'll have to pop the hood and plug into an outlet every time i park it (sounds miserable, no thanks). I also found this solar charger on Amazon that can charge through the 12v cigarette lighter, which would be doable but I don't think that will work since the 12V doesn't work when the car is off? Can anyone confirm? Any other recommended solutions?

 

[thennen]

My son bought a used Corolla that did the same thing, plus a couple other symptoms. His has an aftermarket remote start that ended up being the culprit. I located the two 30-amp fuses for that inside the steering column. Removed those and the problem went away. He had replaced the battery and alternator, too, plus the starter was failing due to staying energized too long. Best I could discern is that it kept trying to start the car, or at least was failing there and letting some current flow. I discovered it when my meter pegged twice and the internal fuse blew while checking current with everything turned off. Before it pegged, I was measuring somewhere around 250-300mA with everything off.

No way to unplug or otherwise disconnect the theft deterrent system?

Anything else aftermarket that isn't fused?

Does everything electrical in the truck work properly?

If I were in your place, I might consider removing every fuse (rather than testing one at a time), and see if the drain is still there. If not, re-introduce one at a time, checking after each one.

 

[Smitty114]

As far as i know everything electrical works. I think the 12V may not work actually but that hasn't worked in years, well before this problem.

Nothing else that is aftermarket.

 

[thennen]

As far as i know everything electrical works. I think the 12V may not work actually but that hasn't worked in years, well before this problem.

Nothing else that is aftermarket.

Then I would test the functionality of everything - windows, door locks, defroster, fan (all speeds), heated mirrors and seats, lights, flashers, turn signals, trailer wiring, whatever you have. Make sure things work as they should. Something that doesn't work right might provide a clue.

I also would be cautious about ruling out things that don't work as being possible culprits. You should still de-fuse or disconnect those as you troubleshoot.

Then look into disconnecting the theft deterrent system. I'm assuming there's a way to unplug it, but I don't know. Maybe you can find that on the forum.

I'm no expert, that's why I would eventually (after all this other stuff) get to the point where I had every fuse (and relay if necessary) out. I think 50-80mA when everything is off is about normal, so you need to get to that point. What current are you seeing?

 

[Smitty114]

Then I would test the functionality of everything - windows, door locks, defroster, fan (all speeds), heated mirrors and seats, lights, flashers, turn signals, trailer wiring, whatever you have. Make sure things work as they should. Something that doesn't work right might provide a clue.

I also would be cautious about ruling out things that don't work as being possible culprits. You should still de-fuse or disconnect those as you troubleshoot.

Then look into disconnecting the theft deterrent system. I'm assuming there's a way to unplug it, but I don't know. Maybe you can find that on the forum.

I'm no expert, that's why I would eventually (after all this other stuff) get to the point where I had every fuse (and relay if necessary) out. I think 50-80mA when everything is off is about normal, so you need to get to that point. What current are you seeing?

Well that's the thing that makes it more difficult, i have virtually zero mechanic skills or tools. I'm relying on my local Toyota specialist (who is excellent BTW and have been in business for 20+ years, I use them for everything), and I also tried the Toyota dealer. Neither can figure it out. But from what the Toyota specialist told me, they tested EVERY fuse on the entire vehicle, sans the Theft Deterrent system. It took almost two weeks.

 

[thennen]

Well that's the thing that makes it more difficult, i have virtually zero mechanic skills or tools. I'm relying on my local Toyota specialist (who is excellent BTW and have been in business for 20+ years, I use them for everything), and I also tried the Toyota dealer. Neither can figure it out. But from what the Toyota specialist told me, they tested EVERY fuse on the entire vehicle, sans the Theft Deterrent system. It took almost two weeks.

That does make it tough. You at least need a voltmeter and the ability to read milliamps. Physically hooking up the meter isn't difficult. If you know someone who is familiar with connecting a meter to read milliamps, then it's just a matter of reading the number (make sure your dome light is off, tailgate too). If it's much higher than 80mA, write it down, then one of you can remove fuses one at a time while the other watches for the meter to go down. If it does, you need to look at what that fuse controls. If it doesn't, leave those fuses out and proceed to the next fuse box and do the same thing. Might be 3 or 4 fuse boxes total, but I'm not sure. You can locate them using your owner's manual. If the number never goes down, you may have a damaged wire somewhere.

If you decide to do this, a tip: take clear pics of each fuse box before you start. Not mandatory, but it can be helpful to see how things were before you started. And take your time, there's no rush.

 

[randy88fj62]

You need a multi-meter that has the clamp on the end. You place clamp around hot wires and take the readings. You can then slowly start to rule out circuits.

Non OEM aftermarket wiring would be my first check. Pull the driver's kick panel next to your left foot and there will be aftermarket fuses in there. Usually the security system is installed there.

What aftermarket things do you have?
after market Seat heaters?


You need an electrical specialist if you cannot do this yourself.

A side fix to keep you going while you figure this out is to disconnect the battery every single time you park it overnight.

 

[Trumpet]

[MENTION=65779]Smitty114[/MENTION], what part of the country are you in?

 

[Smitty114]

You need a multi-meter that has the clamp on the end. You place clamp around hot wires and take the readings. You can then slowly start to rule out circuits.

Non OEM aftermarket wiring would be my first check. Pull the driver's kick panel next to your left foot and there will be aftermarket fuses in there. Usually the security system is installed there.

What aftermarket things do you have?
after market Seat heaters?


You need an electrical specialist if you cannot do this yourself.

A side fix to keep you going while you figure this out is to disconnect the battery every single time you park it overnight.

Aftermarket radio/backup camera is the only thing i have non-OEM. They were installed at the same time, and all 3 places i've taken it have determined those are not causing it. We disconnected them and the battery still had a draw.

Thanks for the advice though, I may have to do that in regards to disconnecting the battery while parked, although annoying.

 

[Smitty114]

[MENTION=65779]Smitty114[/MENTION], what part of the country are you in?

Atlanta GA

 

[duffdog]

I don't buy the "can't figure it out" diagnosis. Any good car audio/car alarm shop should be able to figure this out for you in 1 day. It is possible that the actual starter motor or relay has a short in it, making checking fuses useless.

It is not possible to fail to diagnose something like this if one has access to all the wiring and fuses.

All that has to happen is to hook up a meter to between the positive cable and the battery and start removing things that connect to the positive wire. When a thing is removed that causes the current flowing through the meter to drop, you found the problem. That is the whole thing, there are no other steps.

 

[Trumpet]

I don't buy the "can't figure it out" diagnosis. Any good car audio/car alarm shop should be able to figure this out for you in 1 day. It is possible that the actual starter motor or relay has a short in it, making checking fuses useless.

It is not possible to fail to diagnose something like this if one has access to all the wiring and fuses.

All that has to happen is to hook up a meter to between the positive cable and the battery and start removing things that connect to the positive wire. When a thing is removed that causes the current flowing through the meter to drop, you found the problem. That is the whole thing, there are no other steps.

Pretty much what I was thinking. Draining a battery in 48 hrs is a large draw, between using a ammeter and a thermal imaging camera it should be easy peasy to lock it down and diagnose to the module it in a few hours.

Especially if the battery is fully charged and the vehicle is cold (un-run). You're taking about a 2~3 amp hour draw to flatten a battery that quickly.

[MENTION=65779]Smitty114[/MENTION], if you were local I was going to offer you my help, but you're 14 hours away. It is solvable, you need a specialist. They are out there.

 

[BlackWorksInc]

I don't buy the "can't figure it out" diagnosis. Any good car audio/car alarm shop should be able to figure this out for you in 1 day. It is possible that the actual starter motor or relay has a short in it, making checking fuses useless.

It is not possible to fail to diagnose something like this if one has access to all the wiring and fuses.

All that has to happen is to hook up a meter to between the positive cable and the battery and start removing things that connect to the positive wire. When a thing is removed that causes the current flowing through the meter to drop, you found the problem. That is the whole thing, there are no other steps.

You'd be surprised on a modern vehicle, you could have a module that intermittently pops on and off and pulls just 100milliamps extra and kills the battery over-time. Not to mention your attempts to diagnose it "reset" the module and so it behaves during your testing.

I currently have a 2021 Highlander HV that sat on the lot since Oct, the battery died and the ECM is fried. Not sure if the draw killed the battery or the ECM killed it, won't know until I have a new ECM to test with (which we have no idea when it will come it at this point...)

~

That being said, back to the OP's dilemma , get yourself a decent DMM and an Amp Clamp; or if you trust your skills you can do a direct inline measurement. You're going to want a good reliable copy of the EWD and the power flow of the vehicle to start with. Toyota has done some odd wiring choices through out the years (I had one Avalon that was killing the battery because there was a short in the driver's power lumbar adjustment, that apparently is fed directly through one of the main ABS fuses for some reason so it bypassed a lot of interior circuits and you really had to hunt for it in the EWD. I also had a 3rd Gen 4Runner that had a draw because an interior bulb shorted and didn't light up but drew a quarter amp.)

My guess is that you have something not going to sleep or some odd electrical gremlin in a circuit that is not switched by the ignition circuit.

 

[waypoint]

Verify your door switches are working e.g. with all doors closed and you click LOCK on your key fob, does it beep once and lock?

I've seen vehicles where a door switch fails, and module(s) on the bus don't go into sleep mode which causes increased parasitic draw.

 

[BlackWorksInc]

I should note after about 30-min or so you want to see less than 50milliamp draw, anything more is indicative of a parasitic draw that's unacceptable.

 

[Smitty114]

Thanks for all the comments everyone, I will certainly try as much of this as i can. If i can't find the issue, I'll start calling around local mechanics with the specific issue and really emphasize the draw/electrical/fuse/testing will be needed to solve the problem.