Alternator quit on 2012 4x4 SC tonight! Didn't see a warning light??

Well, my Christmas visit to my sis's house got interesting....as I left the driveway, I noticed my airbag warning light was lit....huh? Kept going. 20 minutes later, the ABS and Brake warning lights came on...now I'm worried. 15 minutes later I'm pulling over as my headlights are barely lighting the road. Engine still running, but can't shift from park into drive. Popped the shift override plug out and placed in drive. Four miles from destination...barely see the highway. Two miles later, voltage dropped enough that the engine was barely running. Pulled off the road and called my Bro in law for a pull to his house. My truck has a tad over 50K on it, but I do have winch, lights, and stereo amp which I have been concerned would kill my stock alternator. I will test the regulator before I'll spring for a new-rebuilt. Weird thing is no charge warning light came on! I checked the warning light symbols in the owner's manual. It showed there should be a warning light icon of a battery to indicate charge fail. No warning light for charging system ever came on. I checked the dash panel pre-start lights to see if one lit, but no battery symbol. Is there no warning light on single cabs? I'll hang a AutoMeter gauge soon as I hate dummy lights, but no warning light? Anyone confirm? Anyone had alt. fail on 2012 or newer? I have never run though deep water or used the winch so mud or overheating causing the failure is out.
Scott

 

Bad battery. Same thing happened in my honda. Everything went crazy and then shut off.

 

I second the bad battery. The truck was generating 14 or so volts but faulty battery couldn't accept any of the charge..

 

Same thing happened to me, at least I got 85,000 miles out of mine. But really, same exact thing, I thought the truck could run with just alternator only, it can't if the battery is totally gone. I had no warning either, just all of a sudden battery took a dump.

 

You live in a warm area - heat shortens the life of batteries. Get yourself a Northstar AGM for years of trouble free operation.

 

They say you should replace the batteries a lot sooner these days too due to the higher amount of technology in cars requiring more of our batteries. If I remember right, they say you should replace more often so as to not potentially damage the electronics. Not sure I believe that with the Tacoma or vehicles in general. Maybe high tech/ luxury cars.

 

With all the lights, radios, and other crap I can understand that.

 

Thanks guys. I'll try a new battery first and check charging voltage. I just serviced my truck during which I load tested the battery (last Thursday). Battery dropped to 10 volts @ 300 amps which is on the edge of the "replace" scale on my carbon pile tester. I called a local battery warehouse trying to get a yellow top, but he told me they stopped selling them due to come-backs. He was supposed to get me his best AGM battery, but did not call. With the holiday coming, I let it slide. Go figure...
Thanks again. I'll know what's up tomorrow...all the stores are closed today and my truck is 25 miles away or I'd test the charging voltage and battery.
Have a Merry Christmas,
Scott
P.S. Nice dodo bigfoote13!

 

Yeah sounds like a bad battery to me too.

 

Battery is used to keep ECM, clock, radios memory correct, and to start the engine. After starting, the alternator kicks in and the voltage regulator controls the amount of voltage going to charge the battery and power the truck accessories. So now the alternator/regulator goes bad, you're still driving but now you're draining the battery until there's no more voltage left. Pull the alternator the regulator in which it's built inside the alternator, and have auto parts store check it. Suggest to get a REMANUFACTURED alternator if all possible instead of rebuilt. As far as car part failures all car parts are not 100% perfect, that's why there's a 3 year 36 months warranty. https://www.youtube.com/watch?v=ceABHQnI8HM

 

I am old school in the head with a 2013 Tacoma in the garage. I was thinking alternater right off but after reading this we are in the minority billybob...
I still have the original battery in mine. I'llc be paying more attention to that now...

 

Thanks for the reply, hope it works out whether it's the battery or alternator. Let us know what was the fix?

 

Start the truck, remove the ground lead from the battery.

If your alternator is charging, your truck should keep running.

 

Sorry, but this is a terrible idea on a vehicle loaded with multiplexed electronics. A very easy way to cause voltage spikes that will destroy ECUs, gauge clusters... the list goes on. I'd recommend a proper diagnosis - starting with the battery as always. Charge if needed, load test, if it passes, then test the charging system voltage and amperage output, and voltage drop between the alternator and battery.

 

Sorry Kyle, you're thinking about much older vehicles, this is not necessarily the case with new vehicles.

Billybob, your post sounds logical, but is incorrect for this truck.

I don't know why everything shuts down when the battery goes out, it doesn't make sense because you think the alternator is going to keep everything powered up, but it doesn't.
I drove to a restaurant to eat with family, came out and truck was dead, nothing was left on, no warning like hesitation to start beforehand, nothing. Got a boost, thought I'd drive a couple miles to the auto parts store, the dash flashed off and on, the headlights flickered, stereo reset itself over and over. Luckily parts store was less than five minutes away. Battery replaced, everything worked like new. I know it doesn't sound like what would happen traditionally, but it is what happened.

 

And that is what killed your battery. That is what load testers do to marginal batterys. imo of course.

My advice, fwiw: get a decent VOM (not a $10 Radio Shack). After the truck has sit, preferably overnight, put the leads on the BATTERY POSTS, should read at least 12.7V, then have someone start the truck. IF the battery is good, the voltage will drop to 12V, maybe a bit less The truck will start. V will immediately go to 13x maybe 14x then gradually come back down in the 13x range. My truck runs at 13,7 at idle. Important: battery connects must be clean, and I don't mean just look clean. Clean them, it's easy. I do this at least once a year, although they never look bad.

If you replace the battery and you still have trouble, it's probably the alternator.

Edit: forgot to add, if you pull the neg cable while the truck is running, it best be a truck that was made in the 70's.

 

Verdict: alternator failure. So I drove out to the boonies where my rig was resting. The battery was slow charged overnight @ 2 amps by my bro in law. I load tested the battery...stayed in the green. Started the engine. Voltage at posts with engine running: 11.5V. Drove home on battery only (25 or so miles). I called the dealership and talked to service. Service advisor agreed, based on the symptoms, that the alternator has failed. I talked to parts. Gave him the numbers for the re-man and the regulator. They can't get either one until Tuesday. I will remove the alternator for internal inspection and further tests in the morning. Bottom line...$$$$. I purchased an Exide Edge AGM battery before my trip just in case the root cause was the battery. Wish I could get off that easy...I rarely do.
Scott

 

Did you test voltage drops between the alternator and battery terminals during your testing? If not, I would strongly recommend doing so before removing the alternator.

 

Voltage would drop between the cable lug and the battery posts if corrosion was the culprit (weak charging of the battery). Testing was done at the cable lugs which should rule out a weak connection between my volt meter and the alternator (my load tester has jumper cable type clamps and also tests alt. output). The battery suffered a hard drain on three occasions (first load test, driving the thing to stalling, and second load test) yet still rebounded and got me home. I've had several sudden deaths of batteries due to a bad cell, but it appears this has been ruled out. I'll do what you suggest anyway as it's easy. But with no charging voltage present at the cables, I conclude loss of charging is likely due to regulator failure as the alternator has low mileage. I know that sucker has been through the ringer as I drive 2+ hours each day with the stereo cranking and headlights and daytime running lights on. I've read that the alternator is rated at 80 amps. My stereo amp can suck more than half of that all by itself. Anyway...I'll give it a shot. Looks like rental car time.
S.

 

My post from 2013 about total draw is sorta prophetic. Guess I saw this coming:

"Run an LED light bar and (2) 8" spots. You and your alternator will be happy. This thread has me thinking hard.........I have four KC 8000 @ 130 watts each and a new Punch 400W amp.......Never had a problem with only the lights, but between lights and amp I bet I will! The lights and stereo will likely draw around 60-65 amps with the stereo at modest gain. Good thing I have the lights on two switches. I can run two or four. I run each pair of lights (two floods and two spots) on 12ga. wiring with 20amp fuses and so far no blown fuses or serious heating of the wiring."

Ca Taco, Apr 23, 2013 Edit Delete Report