Battery light I have a 2005 toyota avalon and a couple of wks ago, i replaced my battery because i had a dead cell. I was told that the voltage in the new battery was too low and that i may need a new alternator, wks went by and i hadnt had a problem. last night i noticed that my battery light popped on and went back off, but the dashboard lights never blinked or went out. I unhooked post to the battery to see if in fact the car was running solely off batery and cut off, however the car continued to run with the battery post being disconnected, so i figured it cant be the alternator. What could possibly have caused the battery light to come on and off randomly.

SOURCE: Low voltage, the battery runs low when running the car

What is the voltage you are reading? Is it below 13.2 or so? Also have you checked the current with the engine off to see if something else is working that should not be on. I ran across this twice while working on a truck and car. A relay that was wore out keep trying to close and would drain the battery every couple of months. Sometimes you can hear them clicking or buzzing. Touching them sometimes they are warm or real hot. But that is not a sure sign it is bad. In my Trailblaze they get hot but are ok. Another thougth is the belt on your alt, correctly set to spin it at the right voltage. I have ran across this many times lately with serpatine belts.

SOURCE: Brake and Battery dashboard lights coming on at same time

Check looseness or corrosion on the leads and wiring at the battery terminals. Check for looseness or corrosion on the alternator connectors. With vehicle started and reved to 2000RPM, use a voltmeter to measure voltage and that measurement should be between 13.5-14.8. If you're unable to achieve this voltage have your alternator checked at autozone or advance auto, its free. Hopefully this helps

SOURCE: 2002 F150 Radio went dead, noticed voltage

The gauge in your truck reads the alternator output. Following are the possible causes:

1. Belt is slipping
2. Battery is shorted
3. Poor connection at battery or to frame
4. Alternator failing

The fact that it came back after turning off the heat and lights, I suspect the belt, and would start there.

Justin Fitzgerald

• 543 Answers
• Posted on Nov 28, 2011

SOURCE: low battery voltage light battery won't hold charge 2002 S60

Agreed, you can do one of two things. Replace the alternator, or get some new brushes and try out your soldering skills. Good luck.