1st Gen tundra battery drain

still got trouble. Disconnected starter and alternator cables, removed all fuses, I still have a battery drain. Anyone know what else it might be?
Possibly a computer drain?

 

On my sequoia my battery drain was the stereo. Pulled that fuse, no more drain.

 

As in still got trouble after your first post 4 months ago ?

https://www.tundras.com/threads/battery-dead-after-four-days.100087/

When you say all fuses, even the ones underhood in EG bay ?

Had you installed anything just before you started experiencing this problem in Dec 21 ?

Did you follow any of the T/S procedures mentioned in your initial thread ?

https://m.youtube.com/watch?time_continue=1108&v=YC--MLNIbik&feature=emb_logo

 

Aftermarket alarm or remote start could be a culprit.

 

My thread:

https://www.tundras.com/threads/mysterious-battery-drain.89893/

 

The truck is stock. No add ons. I bought it used. I would like to know what is an acceptable battery drain is and what might might be connected in the wiring that is not fused.

 

Mine was a 7 pin trailer harness / brake controller that was added aftermarket.

 

I hate to say it, but the way any competent mechanic will use is exactly shown in the video posted above.

Once you can trace it down to a specific circuit, you'll can draw the possibilities down from a hundred to half a dozen, and you can isolate those half-dozen to be sure.

Most powerful thing you can do is set yourself to test a meter to show how much draw is on the battery at rest as it's showing, then slowly go through the fusebox in the engine bay, pulling and reinstalling fuses one-by-one until you find the drawing stops.

I suspect you're going to find it's the fused lead to the cab fusebox. If true, you'll reinstall the last fuse you pulled in the engine bay fusebox, leave your meter testing draw at the battery, then remove each of the cab fuses and check for draw. You'll quickly see which circuit your draw is happening on.

At that point, if it's not obvious what's causing it just by the fuse, you can check the electrical wiring diagram (EWD) for your year and cab style to see what that circuit feeds in the car, and go one-by-one on those.

It's a tedious process which nobody wants to really do. But without having an actual meter setup to test draw on the battery as shown in that video, you (A) have no way to know how much is drawing on the battery and at what rate BEFORE, so you have no clue if you fixed it AFTER, and (B) there's no real way to isolate where the problem is.

Vehicles have thousands of circuits. If yours is truly stock, and you have no add-ons, and you're positive the dealership didn't, for example, put one of those shitty KARR aftermarket keyless entry/security systems on it (i.e. you know your truck inside and out!) then it could be any number of things.

And honestly, you may want to look really closely under the dash below the steering wheel for any black boxes or other things, in case a previous owner installed an alarm at some point, or if you see any spliced wires. The KARR systems were sometimes tucked into the driver kickpanel.

 

Shouldn't the presence of the KARR system be obvious by it's unique fob?

 

Possible, but requires us to assume owner actually has a fob and isn't just using a key, and also knows what an OEM fob would look like.

 

the key fob has toyota logo. With (all) the fuses removed, cab and ruder hood still shows brattery drain..This is the reason I I need to know if there is a possible electronic circuit that is not fused frome either fuse box. where can I find a wiring diagram without having to buy a manual?

 

Look no more, my friend. https://www.tundras.com/threads/ultimate-wiring-diagrams-collection.81448/

PS - just because you have a stock key fob doesn't mean you don't have a KARR system. The factory fob would still theoretically work if one was installed. If your truck was originally sold by a dealership in the SW USA, from TX diagonal to NorCal, all the way down to San Diego, any state in the triangle that would make, you may have a KARR system installed. I've seen those installed from trucks sold in other places, but the majority of people who've posted theirs on here had trucks from that cluster of states.

 

Every circuit on a stocked Tundra is fused either by Driver Side J/B or Under Hood J/B.

 

I'd be interested in seeing pics of OP's battery to see if anything unexpected is hanging off it.

But that said, there's nothing stopping a PO from installing something on the hot leg of a fused circuit if not something direct off the battery. I think it'd only be possible on the engine bay fuse/relay box though.

I'd really like OP to measure current draw and post back with that info.

 

There have been numerous troubleshooting questions asked, suggestions given not only in this thread but especially in Jan thread. Unless OP wishes to offer comments of items he has checked, it's hopeless IMHO.

"Have the new battery load tested, even brand new they can be bad, have a dead cell, etc."

"Or the door switches"

"One post on here recommended turning off the headlight switch as the relay sometimes drains the battery"

"On my sequoia my battery drain was the stereo. Pulled that fuse, no more drain."

etc....

It's almost like pulling teeth....

 

I dunno, I've had to pull my kids' teeth a couple of times already, and it was definitely less work than this.

 

I know I missed an important.. I did not pull the 140 amp fuse..May have a draw by the alternator. I also didnt have the wiring diagram at that time. Will recheck everything this weekend, post results then

 

updaate. Isolated alternator from circuity, still showed .o85 ma drain. Started pulling fuses in engine compartment fuse box. Pulled no 3 and load drop,d about .o45ma, that was the fuse for cabin lighting and others..pulled no 4 for obd, on board dianostic, drop went to zero. I let the truck set for 5 days. I started it this morning was like it was a new battery.. I put no 3 fuse back in and will wait another 5 days and will post again. Thanks to all for the help, most of al for wiring link.

 

That's interesting on the interior lighting. You didn't happen to have one of your doors open while testing, did you? If all doors are closed and the key is in OFF position, and you didn't recently unlock so the courtesy light is off, you shouldn't be seeing much of any draw there at all (unless an you have an under-hood light on to that circuit)

It's normal for OBDII to pull draw. Pretty sure your ECU is on it, but ... all of the above is without looking at the EWD.

 

All doors were closed. Ithink every thing had went to sleep.I have had this problem since I bought the truck and finally decided i was going to fin the draw or else. When I pulled the two fuses was the first time I had no draw. Now I am waiting to see which fuse is the one that kills the battery. I hope it turns out to be the obd which I think is in the ecu. Will know in a few days . later.