98 Runner battery draining to dead

Okay electrical geniuses (or dudes who may have had this problem):

I’m the third owner of a well-maintained ’98 4Runner with 115K miles and some very modest mods (courtesy of forum member AOWRS). I bought this sucker to take on trips, run the mountain bikes around and occasionally tow the motorcycle, it’s been great except for the $1100 timing belt replacement last week. Anyway I have a issue that I need to take care of but we can’t figure out what it is.

Over the summer I went out to my truck to find a completely dead battery. I hadn’t driven it for a few days but I did not leave the dome light or anything else on. The battery was a big Interstate battery that was only 6 months old. After a jump start and a long drive I took the truck into the battery store where the tested the battery and alternator and they could not find a reason for the dead battery. Just to be sure I had them warranty my battery and give me a new one at a pro rata cost.


Last month while at the Toyota dealership I had them pull the old service records and it seems that the last owner took the truck in because she was complaining that the battery sometimes goes dead after not driving it for a few days. The dealer recommended a new starter for $710. The previous owner did not replace it at the dealer but I don’t know if it was replaced. Whatever the case, I don’t think it’s a starter issue because it always starts right up. Unless the battery is completely dead.

Anyway, yesterday I went out to find... A completely dead battery. No click-click noise, just the dimmest of dash light. I hadn’t driven the truck for four days but I have done that many times.

So, what’s the deal?!?!?
We did a little forum searching to find a way to try and run down what could be draining the battery and we did come across a technique to find a draw but it led us to find this weird issue:

When we pulled the negative battery cable and put the multimeter in line we found that the modest draw on the battery went down a bit when we pulled the fuse for the dome lights (even though the light wasn’t on, what is up with a draw when nothing is in use?) I would just pull the fuse and not use the dome lights (a small hassle) but the same fuse seems to control the power locks (big hassle). I don’t use the key fob but I do use the power door lock switch to unlock the doors and hatch so I don’t want to disable that sucker. I don’t know why the doors would be on the dome light fuse but maybe it’s related to the Toyota security system (which I also don’t use and would be more than happy to take out if I could still use my power locks).

-If anyone else with a ’98 is curious, go pop your hood, pull dome light fuse and see if you door locks work... I’m curious at least.

So, thoughts anyone? I really want to be able to park my truck for a few days at a time with wondering if it is going to start. Any help on how to figure out what is causing the draw or if this ever happened to you what you did to fix it would be greatly appreciated.

Thanks!

 

You like the word "sucker".

Also, you should mention that your truck has a remote-start setup, of unknown origins...


Andreas

 

Disconnect the negative cable, get a DVOM and connect it between the negative cable and post on the battery and start pulling fuses untill the amp draw drops.

 

We did that and ran into the situation that I described. Now what? Thoughts?

 

James,
I have a nice DVM, but we found ourselves a bit puzzled by the findings when using 'ADC'. Do you have some simple setup tips for a DVM that would make this painless?


Andreas

 

Set the DVOM to amps, usually on the 10 amp scale and hook it up between the cable and the battery, it should read around 10 milliamps which is normal. Sometimes you have to give the cars computers a little while to sleep
Sorry, my wife was rushing me to get off the computer so I skimmed over that part,

sometimes the dome light circuit is on kind of a timer if you had just shut the door. How long did it sit with your reading and how much was the draw?

Another thing, are you sure the battery was dead? Did you check the voltage when it wouldn't start? I had problems in my wife's 4runner with the negative cable cracking on the inside so it would seem like the battery was dead, I would jump it and it would be fine until sometime later it would do it again.

 

I had a similar problem like that on mine. It turned out that the rear cargo light shorted out. When I pulled the light bulb the amperage dropped. How a bulb can draw current when it isn't supposed to have current going to it is beyond me. Long story short if the problem is in the dome light circuit check the bulbs and then check the switches. Parasitic drain is no Buenos.

 

I think we counted between 15 & 17 seconds before the draw settled down to 50 mA (if we read it right).

Interesting tip on the ground cable - Robb did not check the resting voltage before jumping it. (not the sharpest tool in the shed)


Andreas

 

50ma is enough to drain the battery. I have had simular issues with my truck. ended up being some aftermarket gauges I installed using way too much power to remember what color I left them on. I just swaped some wires around and got the drain down to around 10-15ma which is ok. Still will drain itself over about 5 days to a week but can't figure out where that drain is coming from.

 

So maybe first thing to check would be the aftermarket remote start, some are wired into the door where the door has to be locked to start it, so if that is your situation, it could be the draw. Try to find an inline fuse for the remote start system and pull it, then try your test again and see if it changes.

 

That is a very interesting idea. I'll look into it. Thanks.

 

Mine is doing the same thing, only there is a constant click under the hood. The only thing I have done differently is I put an American flag in the passenger window and had to leave it down about 3" overnight. Today, no dash lights, no start just click. Any ideas? Hope it's not a conspiracy related to the flag..lol.

 

If it is not the remote start or alarm

I would look at the glove compartment light I had one just about drove me crazy.

Light on with the door open so at first I never gave it any thought .

Battery voltage when it won`t crank is a real good idea.

For some strange reason I have seen poor grounds cause the battery to drain. It makes no sense but up grading all the ground wires cured the battery drain..

Battery top clean and dry that a bridge is not formed between the two posts