changed battery but battery light still come on when car is turned off

Asked by Aug 15, 2017 at 10:16 AM about the 2002 Pontiac Grand Am SE

Question type: Maintenance & Repair

I went to a well-known store to have my old battery checked. I was told that it was dying because it would not hold a charge. If the car is off for more than 10 hours, then it would not start. with the old battery, I was also told that the problem is not the alternator because it charges the battery when the car is running and driven for some minutes. A church member told me that the alternator diodes might be going or gone bad. So, I bought a new battery and just had it installed. The terminals are properly connected, and the battery is in place, when I start the car, the battery light goes out, but comes back on after the car is turned off. Why is that happening? Is it the diodes?

2 Answers


A battery light on means there is a problem with the charging system and usually on when the engine is running, not off. With the engine running probe the battery with your multi meter, it should be around 14V. With the light on after the engine is off, it sounds like you have an ignition switch issue. or other wiring issue that is draining the battery.

2 of 2 people found this helpful.

True. Agreed with Tom I have had cases when the Alternator has still sucked the juice out of a battery even when not running... it's as if charging relay (by the fuse) is sticking.

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