Battery light remains on

Tiny
MALLYBOY
  • MEMBER
  • 2013 TOYOTA AVALON
  • 3.5L
  • V6
  • 4WD
  • AUTOMATIC
  • 206,876 MILES
I began to notice that my Venza is draining battery and any time I start it in the morning, the battery light remains on and after a short period it off. What are the causes of this? I have check fuses and they tested okay, check relays and tested okay, check battery terminal for corruption, still okay. Could it be alternator itself or the belt that is the problem?
Thursday, September 9th, 2021 AT 1:55 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
Hi,

Always check the belt first to make sure it is tight. However, if it is loose enough for the alternator not to turn, chances are you would hear it.

This sounds like it is related to the alternator itself. First, I attached the wiring schematic for the charging system below as a reference. Here is what I need you to do:

Before starting it in the morning is when we need to test the alternator. we need to check the voltage output from the alternator when first started. All you will need is a voltmeter or a multimeter.

Follow the directions in this link and let me know the results:

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Let me know both the battery voltage with the engine off and then the voltage when the engine first starts with the alt-light on.

Take care,

Joe

See pics below Note: The schematic was one page long. However, I had to cut it in half to make it readable for you. I did overlap them so you can follow from one to the next.
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Thursday, September 9th, 2021 AT 6:34 PM
Tiny
MALLYBOY
  • MEMBER
  • 309 POSTS
Problem solved after voltage test and confirm that the alternator was faulty.
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Saturday, September 11th, 2021 AT 1:05 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
Hi,

Thanks for the update. I had a feeling the alternator was the issue. Regardless, good job and I'm glad you got it fixed.

Take care of yourself and feel free to come back anytime in the future if you have questions. You are always welcome here.

Joe
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Saturday, September 11th, 2021 AT 9:05 PM

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