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Discussion Starter #1
Wife was driving home and the battery light indicator came on. She made it home. I was out of the house when it happened.
It looks like the cold weather was the culprit but it was only 45F this am. I won't be able to check it until after 5PM.
It could only be either the battery or the alternator. Which one is more likely? Any one care to guess?
 

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Discussion Starter #3
With engine off, battery at 12.3V. Battery was dated 2018, so it's fairly new.
Tried to start and it started but starter was a little slow.
Engine running, battery at 11.9V.
I think the alternator died.
 

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I'd venture a guess at the alternator. Do you have a code reader? You have a MIL on so there should be a code stored somewhere on one of the modules that will point you in the right direction. My '03 XL informed me "Check Charging System" or something similar to that on the HUD so it was pretty obvious what the problem was. I had it off in an hour and had AutoZone confirm it was bad before getting a new one.
 

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Discussion Starter #5
Thanks.
I will pull it out and have it bench tested at the alternator shop.
If bad, I will just get it rebuilt.
 

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I would suggest getting a code read first if at all possible, on the off chance it's a grounding or battery issue.
 

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Discussion Starter #7
It was a bad alternator. I had my factory alternator rebuilt for $80.
All good now.
 

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If it’s fillable, maybe low usually closer to the positive. My gel batt lasted 7 years just changed it 2 months ago. Distilled water is .99 @ Walmart. Happy Safe Holidays
 

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My experience has been that either the battery takes out the alternator.. or the alternator takes out the battery... I usually end up needing both
 
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