What would make the battery light come on intermittently?
Asked by mrbelk Jan 12, 2014 at 07:46 AM about the 2005 Mitsubishi Galant ES
Question type: Maintenance & Repair
2005 Mitsubishi Galant ES. Battery light comes on at start up then goes out after a few minutes. Mechanic tested alternator and found no problem. Battery was replaced. Symptom continued. After several weeks of driving with this condition, the car refused to start. The battery was completely drained. Mechanic tested the new battery and found it to be bad. Replaced with new second new battery. Symptoms disappeared totally for about 2 weeks. Now back to same symptoms of having the battery light come on at start up. Appreciate any troubleshooting tips.
5 Answers
yetilikesbeer answered 10 years ago
Replace the altenator. The battery light is only on when the altenator is not charging your system. After starting the light should go out asap. It's not so that tells me that the altenator is weak, and once the light does go out I'm thinking it's not charging at full output, hence the new dead battery. Did the tech say what the voltage was of your charging system when it was tested. The battery should be around 11.5 to 12.5 volts and once the vehicle is running the alt. should bump your charging system up by atleast 2 volts. It is the volt differential that forces current to your battery to charge. A carbon load tester with volt reading is much better for testing batteries or charging systems but the younger techs are usually a little cautious on using them on newer vehicles.
I agree. If you know that the battery and all connections are good. And it starts without issue when battery is fully charged then I would replace the alternator. All because it tests good does not always mean that it is performing at peak output all the time.
Also have you checked your alternator belt? Is it making a squealing noise? Is its tension correct?
Thank you. New alternator installed today. So far so good.
