So I’ve been fighting some sort of electrical drain on my truck for quite some time (and by fighting I mean jumping it if I don’t drive it regular enough and just dealing with it), but I recently started trying to figure out what’s wrong with it. As a start, I gutted all the extra electrical components I’ve added: front/rear fog lights, extra switch for rear window, extra 12v outlets. I had an issue with my rear hatch to where the sensor wouldn’t recognize the door as being shut, that’s been fixed.

Before removing all those, if I didn’t drive it every 2 days, the battery would be so dead on the 3rd day that the door locks wouldn’t even work the battery was so dead. Now, I let it sit for a weak, and it still had power, but not enough to turn the motor over. I’ve replaced the battery, and the starter/alternator have both been replaced at some point over the last year.

I hate electrical, and have hit all the obvious fixes, and I’m not real sure where to look now. Any suggestions or “smoking guns” I could look for?

I would start with the engine cold and see what kind of amp drain you have, if more than 30 mA give or take a few.

Take an multimeter ($10) and switch it to dc amps and disconnect the negative battery wire, then clamp the leads of the multimeter to the negative battery terminal and the ground wiring and switch it to DC amps. Measure the amp load, it should be only a few mA. Then, start pulling fuses one at a time and putting them back in until you find the culprit. Once you find the offending circuit and fuse, identify what fuse it is and hunt down your issue.

EDIT: Eric the Car Guy explains it better than I can:

How To Perform a Parasitic Draw Test - EricTheCarGuy - YouTube

Here's the best video I know of for tracking down a parasitic drain. If you have a drain you'll find it this way.

We’ve had pretty nasty weather ever since I posted this, but I was able to get out and fool around with it today. I followed the advice in the YouTube clip and this is what I got.

When I initially connect the leads, I would get a small spark, not sure if that’s normal or not. When I initially connect it the amps would momentarily spike to bewteeen 0.15 and 0.26 amps (150-260 milliamperes according to google). Then it would drop to 0.06 for 3 seconds, and then drop to 0.02.

I followed his advice of popping fuses until the amps were normal. The “dome fuse 15A” under the hood seems to be the culprit. None of my dome lights are on (in fact I have them all set to off). I looked at the wiring diagram in the Haynes manual and couldn’t find anything that looked like it would be a smoking gun. I went ahead and pulled the fuse to see if in fact the battery drain stops. I noticed that my door locks no longer work, which I don’t see where the dome fuse is connected to the locks in the wiring diagram.

Maybe one of you is better at reading wiring diagrams than I am and could shed some light (no pun intended). Or could tell me if the spike followed by a drop, followed by another drop is normal?

I'm not 100% sure about a 97, but on a 99/2000 etc the dome light fuse is integral to the function of the door locks. It provides power to the circuit which tells the body ECU what doors are open or closed.

That said, the dome fuse isn't your problem. YES the spike and subsequent drop in amps is normal. And .02 amps won't kill your battery in a week.

You need to go back to basics, have your battery checked!

+1 on having the battery tested. I have to ask when you added the fog lights, outlets, did you add them to the dome circuit? Fuse is good?

The battery is ~2 months old. Still think it’s worth having it tested?

Fog lights had their own circuit straight from the battery. I don’t remember what I grabbed from for the outlets, did those years ago. I think I pulled straight from the battery on them too though.

Do you have a stock radio? I've had those wake up by themselves and the CD runs unit lights up...rarely, an alternator field coil will get juiced too....that was a tough one to find...the draw you're showing isn't enough to zap a battery in a couple days...so battery junk or something freakie.

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The battery is probably good then.

Ok. Done any repair work lately? I am thinking it would be better to run the fogs and outlets off a fused circuit but if has worked well for you all these years, keep doing it unless a component (the fog light has water in it) is junk. But that would not explain why the 15amp dome circuit is making things screwy.

When did you tackle the rear window work?

The 2 months old battery is good for good brands and not for some autopart store batteries. Please check the battery. I see A-zone battery going bad on my cousin's pathfinder just in 6 months.

If your alternator is warm to touch even after engine sitting cold can imply it is draining battery. Is your alternator OEM or aftermarket?

Well, fog lights have been completely removed at this point, including all their wiring. They hadn’t been working for some time, and Va state inspection decided to ping me on it this year.

I “fixed” the rear hatch light a few weeks back, same time I gutted all my wiring. Since then it’s gone from ~3 days to drain to a week.

I’ll have to check the alternator next time I get a chance (the 4runners not my DD, the vstrom is). I did replace it ~6 months ago. It’s just a replacement alternator from autozone.

Keep an eye out on that alternator. You may be using that lifetime warranty sooner than later. What voltage output are you getting at the battery with the engine running?

I would still believe that something on the circuit is still open.

What is your aversion to having the battery tested? Just curious.

Pointing the finger at parts that somebody's cousin in Manitowac once found to be their problem is just silly. 2 one hundredths of an amp will not drain your battery in a week.
My Landcruiser draws about twice that and it sits for a month easily.