Battery Light Won't Go Off

Hello, New to TW, I'm located in AZ and the light came on in my '09, batteries only seem to last about 3 years here, if you're lucky. I just had to buy one for my 2017. So, I wasn't having any issues, just the light came on, took it down to Auto Zone, ran a scan, no codes came up. They directed me to O'Reily's, different scanner, maybe something will come up? On the way over there, I then get brake light, traction control light, ABS light???, I was like WTH? So I go in and ask them to check the battery, they bring out the battery tester, look at the belt hook up the battery, proceed to tell me the battery is bad. I asked if they could check for codes since all the other lights came on. No codes. Good news, I have a FREE replacement until July (YEAH)!! Bad news, now the truck won't start, it's 105 degrees outside and I bought the battery down the road at Walmart. It's all been taken care of, but the light is still on. I have lost my job due to this whole Covid-19, so I surely can't afford a mechanic. My husband is not mechanically inclined, so if the alternator needs to be replaced, I just don't know???? I cleaned the cables, light is still on. Anyone know someone close to Mesa, AZ??

 

Hey Kim,
Chime in here, Lots of people in AZ help each other out!

https://www.tacomaworld.com/threads/az-bs-thread-5-0.431790/page-4718

 

When you got the new battery, they should have then checked the alternator. Have the alternator checked. Codes are normally not a issue with bad charging systems, but those systems will start shutting down with low voltage. Get the charging system checked and repaired and everything else should be fine.
Zim

 

How many miles is on the truck? alternator is probably the culprit

 

Yep, battery light usually indicates the alternator isn’t charging. I’d imagine there’s some diys here that would show you how to replace it.. I’d also check into having yours rebuilt not always the longest lasting option but sometimes the cheapest if there’s a local shop that rebuilds them. But first have a full charging and starting system test done at your local parts store or Walmart.

 

First and foremost, make sure the terminals are sparkling clean and tight. The alternator and battery both should've been load tested at the auto parts store but unfortunately, some that work there are limited in mechanical knowledge. Rule out your charging system first and hope the warning lights are related to that but sometimes the traction, abs, brake lights could signal a faulty wheel speed sensor that an auto parts store code reader will not pick up. Buy a cheap harbor freight voltmeter or multitester and check the battery and alternator voltage yourself with truck off vs idling. Battery should read roughly 12v off and around 13.5ish when idling. 2017 is too new for an alternator to go bad.

 

In my experience with Toyotas, if both an emergency brake light and the battery light are on when the car is running its the alternator.

 

This ^ Everyone should have at least an el cheapo multimeter. Folks on TW will explain how to use it.

 

Here is a pretty basic video using a multimeter testing the battery and also showing how you can see when the alternator is charging.
It doesn't get anymore basic than this video so it's a good one for people who are new to this stuff. You can get a multimeter from harbor freight for $3.99 using this coupon. If it is the alternator, here is a DIY on how to change it. If you husband can't do it, then time to roll up the sleeves and who him who's boss and you get in there and do it to it !
https://www.tacomaworld.com/threads/step-by-step-diy-alternator-replacement.384165/
https://www.youtube.com/watch?time_continue=144&v=COJr7OB23Hw&feature=emb_logo

 

My multimeter is one of my most used tools for the car, house and electronics. Learning new ways to diagnose stuff like this is fun and can save a ton of money.

On a separate note, I lived in Phoenix years back and bought an extended warrantee for a battery at Autozone. I never paid for another battery because the heat kills them so fast a I got free replacements for the rest of my time there.

If you can jump start your truck and measure the voltage across the battery while the truck is running, you should get ~13.7-14.7 volts. Once you turn the truck off, you should measure >12.6 volts on a good battery. Then let it sit overnight. If it drops below 12.3, the battery has a drain or is roasted. Doing this helps you determine if you have a bad battery, bad alternator or a drain on the system.

 

Repair TIP.
If you replace your alternator, make sure the battery is fully charged. Take it to the parts store and have them charge it for free. The reason is, when you start the car, the alternator will immediately start charging the battery for the power used during the start. If the battery was low, the alternator will go bat shit crazy charging that battery, and may cook the voltage regulator, or diodes, or other electronic shit that's like top secret. It's like starting a workout with 500lb bench presses....lol. That is all.
Zim