Battery drain (1 Viewer)

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Apr 8, 2023
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Location
Georgia
Howdy everyone. i've attempted to search the forums but haven't really found what I'm looking for.

I've got a 1994 JDM FZJ80. It has a carrozzeria head unit/speakers/subwoofer. It's got LEDs in the headlights, dome light, and tail lights. I picked it up 11 AM yesterday and drove it around all day without issue. Eventually it got dark out and I turned on the lights. On our way back, I turned on cruise control while we were on the freeway and shortly after, I started seeing all the dash lights turn on. By the time I got to the restaurant we were going to, the batter meter was pretty low, the head unit had completely died out, and the headlights and tail lights were dead. Naturally, the thing was completely dead. Even after throwing a jump box on it, we were able to get it started, but it would not stay running for more than a minute or 2 until it would die again.

I got it towed him, took the battery out, and let it charge back up over night. I put the battery back in this morning, drove it around and it was doing fine. Eventually I had to turn the lights on and the defrost due to it being rainy, and I saw the battery meter drop from above the halfway line to below the halfway line. Took it home and let it sit. Took it back out to grab a pizza and about halfway there, the dash lights kicked on. I turned off the lights to hopefully keep the battery alive enough to get me home and right after I turned them off, the lights on the dash went off as well. That only lasted maybe 2 minutes before the lights were back. By the time I got home the tachometer was all over the place, i had no lights, the head unit was dead and when I parked, the automatic door locks didn't have enough juice to even lock the doors.

Initially the thought was that the cruise control just depleted the power since I didn't have any issues until I kicked it on, but I didn't use it at all today and it couldn't even survive running for an hour, compared to the 8+ hours I was out yesterday. The battery is also brand new from Toyota.

I've seen some forums talk about some issues regarding led lights and cruise control, but nothing specifically to what I'm having.

Y'all got any ideas?
 
Yeah initially I was leaning towards Alternator too. Did some voltmeter testing and it seemed like it was functioning properly. Considering the issue didn't start happening until after I had tried using cruise control, we took it out for a spin today and saw the battery dipping a bit lower but nothing crazy, then pressed the cruise control button which immediately prompted all the lights on the dashboard to come on. Turned the truck off, but then it wouldn't start again due to lack of power. Had the auto shop test the battery and they came back saying it was bad so we threw a new one in and it fired right up. Drove for the rest of the day, didn't use cruise anymore, thought everything was cool, but sure enough, later on in the day, the battery meter started to dip again until the dash lights started coming on and everything started getting whacky. Got the battery charger on it now and it was below 25% again. It does seem to be an alternator thing though and I'm thinking that the other things might just be coincidence
 
alt should put around 14.7v initially and then settle to around 13.8 - 14v once the battery is charged up
also, get a load test done on your battery as it could have dropped a cell and if the case will never get fully charged again
 
It's looking like y'all are right for the alternator. Tested with a voltmeter again and noticed that it was never getting above the voltage of the battery. I have a battery charger that also checks the alternator and instead of saying it was "good" it had an exclamation point. So going to focus on that direction tomorrow.

Thanks y'all. Will update.
 
Alright, so unfortunately still having the problem.

I threw a new one in today and after throwing getting everything else back, what I saw on the voltmeter was that the battery at rest was getting up to about 13 and when the car was started it would drop and stay around 12.2. Also, once the vehicle was started, all the dash lights were on immediately.

So at this point I'm still completely lost to what could be the problem.
 
all the dash lights on 'christmas tree' is classic alternator issue and worn / failing brushes the usual culprit

its dropping and staying at 12.2 cause the fuel pump, ignition etc keeping the car running is relying on the battery only and not being assisted by the alternator

probe the positive terminal at the back of the alternator when engine running, if 12.2v there then the issue is within the alternator

the below video shows how easy this fix is

 
all the dash lights on 'christmas tree' is classic alternator issue and worn / failing brushes the usual culprit

its dropping and staying at 12.2 cause the fuel pump, ignition etc keeping the car running is relying on the battery only and not being assisted by the alternator

probe the positive terminal at the back of the alternator when engine running, if 12.2v there then the issue is within the alternator

the below video shows how easy this fix is


I did see that the brushes could be problematic but figured I'd just throw in a completely new alternator instead to kill 2 birds with 1 stone and no luck 😭
 
apologies, i misinterpreted a 'new one' as a battery! too much chocolate easter eggs!

have you confirmed the fusible links are ok for continuity? also check the 7.5a charge fuse in the engine bay

with the engine running what voltage are you seeing at the back of the alternator?

1681090443015.png
 
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apologies, i misinterpreted a 'new one' as a battery! too much chocolate easter eggs!

have you confirmed the fusible links are ok for continuity? also check the 7.5a charge fuse in the engine bay

with the engine running what voltage are you seeing at the back of the alternator?

View attachment 3294977
hahaha it's all good. I should have specified what I was talking about. One of the guys from the dealership came out both on Saturday and Sunday to help me figure out what might be going on. After replacing the battery and replacing the alternator, the call was made for this thing to get towed back to their shop so they could have proper space/tools/resource...etc to get this thing fully taken care of.

Thanks for the assistance and I'll update as soon as I hear something from them.
 
Alrighty so the end result:

After having it sent back to the dealership for them to check it out, it appears that they discovered several bad grounds were the culprit of the issues. Now at full charge, my battery meter shows closer to the 18v vs the midway line, the charge seems to hold, and even though the air conditioner was already amazing, it's CRAZY cold now so it looks like it fixed a few other things as well.

Drove it a pretty good amount yesterday and it appears to be back in all its glory

Thanks y'all
 

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