Battery Indicator on

Hey everyone, I noticed this morning on my way to work, my battery light was on. I have a 05 Tacoma, and since I've never owned a Toyota product before I'm not familiar with it's warnings and quirks yet. Seemed to drive fine, but just in case it was the alternator I didn't use the radio, fan etc. I couldn't find anything in the manual, so my question is: Is this likely to be the alternator or the battery? I cleaned the terminals on the battery and the light is still on. I'm goiung to put my meter on to get the voltage. What reading should I be getting?
Thanks, any suggestions would be helpful.

 

If it's the original battery then it's probably bad after 7yrs, otherwise it could be the alternator

 

I think you should see around 13.5/14volts with truck running

 

Check out that battery

 

I checked the voltage and it measured 14.3V with the engine running. I turned on the fan, radio, dome light and volage drop was minimal down to 14.18V. Battery is 1.5 years old. this is the second alternator according to the gentleman I bought the truck from. He said Toyota used outsourced alternators on these models and when it was replaced under warrenty, Toyota put in a good one. I bought this truck from a coworker that retired and didn't need it anymore.
Funny thing, all day the battery light stayed on while I was doing my service calls, and driving around. I came home, looked for answers on this forum and when I went out to test the voltage and I started the truck, the battery light went out like normal.

 

Maybe check the voltage tomorrow before starting engine............sounds like alternator is working fine. Even though the battery is only 1.5yrs old doesn't mean it couldn't be bad. It does happen unfortunately

 

I may get crap for saying this but I think thats actually a sign your battery is old and dead. I JUST replaced my battery because it wouldn't keep my stereo going. Voltage was reading 14.4 after startup. 14.4, while awesome for those doing stereos, appears to NOT be what these alternators run at. The voltage jumped all over the place once I started running the stereo. I know my voltage was dipping below 12V because my amps would shut off at that voltage.... even though the median voltage was above 13V.

Sounds to me like your battery is old and tired. Its not a for sure test but go to your local auto parts store, they should be able to do a load test for free. You should be seeing 13.6V give or take a few. 14.4 is high, and likely why you have a light. I'll double check the circuit now.


EDIT: I can't find information on the range to trigger the idiot light. If its the original battery, replace it. You can inspect the battery yourself as well. Look for the green 'eye' on the top of the battery. Green is good, yellow is bad, clear bad bad. If the level is low you can add distilled water and see if it helps, but if the electrodes are corroded you might as well just replace the battery. You will see a buncha gunk on the electrodes if they're done.

 

The alternator light is an indication that there is a miss match between the alternator voltage and the battery voltage. I always check the simple stuff first like a loose alternator belt or terminal corrosion/oxidation. Then I fully charge the battery and then test it. For more information on testing a battery, please see Section 4 in the Car and Deep Cycle Battery FAQ on www.batteryfaq.org.

 

It could be the alternator, our 2007 4runner did that and it died on me while coming home one night.

 

Be sure to check all battery cells for proper fluid levels. Mine was low on several cells today. Only use distilled water to refill.

 

Someone with a proper load tester should be able to load test the battery, and check the alt diodes in about 20 seconds.

With maintenance free batteries, if you're having to add water it's more than likely you're overcharging them.

Don't load test an AGM.

http://www.tacomaworld.com/forum/2n...oltage-diagnosis-helpful-reference-chart.html