Flashing battery light on Chevy avalanche Silverados etc

30

Asked by GuruSJ4HS Jun 23, 2019 at 08:40 PM about the 2002 Chevrolet Avalanche 1500 4WD

Question type: Maintenance & Repair

I came across this problem where I noticed
that my voltage gauge in my truck was
fluctuating, let it go on for a little while then
as I was backing in my driveway my 02 Chevy
avalanche almost died out and I lost power
but it came back on, that being said I figured
my alternator was going out so I
disconnected the battery and the truck turned
off, which is a good indication that the
alternator is not working because he
alternator should pick up the power and keep
the vehicle running, I went and got a new
alternator same as you except now the
battery light is flashing on and off and my
gauge and the truck is not even halfway on
the power indicator, I saw one guy on here
saying that he bought a Bosch alternator and
it sends back 5 volts to the PCM and helps
the alternator charge etc, but after doing that
4 times, I learned that maybe I should change
out the banana clip that plugs into the back of
the alternator that goes to the PCM maybe
the clip and the terminals inside of it aren't
making proper connection, because my
alternator is were all good my battery is brand
new and yes I did try the Bosh 130 amp
alternator do not get the 105 amp alternator.
so after changing the banana clip and putting
back in my original alternator this thing is
running perfect my voltage meter is way past
the middle and my battery light has not
flashed since I hope this helps I also cleaned
all the terminals and made sure they were
shiny before I hook everything back up
including on the battery and the little red box
next to the alternator took that apart cleaned
up everything in there, but I definitely believe
that it had a lot to do with that banana clip in
the back of the alternator that goes back to
the PCM and to the starter hope I helped.

4 Answers

30

Just change the wires on the back of your alternator the banana clip and clean up all terminals the battery light should stop flashing and your voltage gauge should go past halfway hope it helps

3 people found this helpful.

daysThis guy is a genius!!! I think we would have went straight to replacing the alternator had I not come across this post. We bought the "pigtail" and were too busy to replace till 90 days later. It worked great! I am still a little hesitant but this appears to be the fix. It was very easy to complete and right now it looks like the right call. Just a suggestion to folks. The replacement part we bought did not have color on the wires,both were white. We marked the wire, to ensure we wired it up correctly. We made sure the black wire from the vehicle was marked black on our part. Thanks again.

This guy is a genius!!! I think we would have went straight to replacing the alternator had I not come across this post. We bought the "pigtail" and were too busy to replace till 90 days later. It worked great! I am still a little hesitant but this appears to be the fix. It was very easy to complete and right now it looks like the right call. Just a suggestion to folks. The replacement part we bought did not have color on the wires,both were white. We marked the wire, to ensure we wired it up correctly. We made sure the black wire from the vehicle was marked black on our part. Thanks again.

I have an 02 avalanche, one owner. Suddenly on day the battery light started to flash. What I found odd is that there was no distinctive pattern. As an electronics engineer, I’ve found, flashing patterns usually indicate something about the issue. In this case, I found nothing about any type of flashing. It was an on or off indicator. The odd part at this point, the volt meter was showing a perfect charging voltage. No voltage drop whatever the the accessory was being used. I went to auto parts store to get the electrical system tested. The alternator tested perfect, the battery wasn’t perfect but good enough to keep a charge and start the truck. Since the battery was old, I decided to replace it. The flashing stilled continued with the new battery. The only possibility left was some thing in the wiring harness. I read several articles about the alternator connector being an issue. I ordered a new one, in the meantime, I decided to clean the old one. Nothing was obvious to the eye. My years in electronics have taught me although the eye is one of the best tools to find a problem, it can let you down. I did what I could to clean out what look like perfectly clean connectors. To my knowledge this connector has never been disconnected from the alternator. I also used a marine base silicone that was extremely hydrophobic. Meaning that it was a lubricant that would repel water and moisture. Cleaning and lubricating that area didn’t seem to work. I ordered a replacement connector from Amazon and it took a couple of days to get here. By the time it got here the flashing battery light had to stop. I have a brand new connector I have yet to use. it would seem that somehow moisture got into that connector and or the top of the alternator where that connector is inserted. Using marine electrical silicone with the water resistance (hydrophobic) seemed to take care of most likely would be a moisture issue. It didn’t work right away, which is why I suspect moisture. After two days I sitting and waiting for the part. I needed the truck before I could make the repair. It’s been about five days since the truck was repaired and I have not seen the battery light flash sense. Within the electronics of more modern vehicles electronic circuitry, there are chassis grounds, and there are floating grounds for certain electronics. My only exclamation at this point is a floating ground between the alternator and the connector was created due to moisture or corrosion. I live in south Florida, and we are in the middle of our wet, rainy season. It feels like it has rained here almost every day since the end of June, it’s literally the middle of August now. I want to thank the others that looked into this connector issue and hope whoever reads this finds my solution helpful. One that doesn’t require the aggravation of cutting and playing with wires are in the electrical system. Thanks for the heads up everyone!

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