NEED HELP Battery light turns on at random

Kgurn1020

Original poster
Member
Mar 2, 2023
43
Massachusetts
Good afternoon everyone. I've been scratching my head at this issue for just about a month now. I have a 2003 Silverado 1500 Ls 4wd that's been dealing with an electrical issue. After taking it in for an alignment the shop said that the battery would not charge, the battery light was on and the alternator wasn't charging the battery. The shop assumed it was the alternator and since I didn't have an option I had them install it. 4 alternators and 3 days later the issue persisted. They had apparently "fixed" it by repairing a faulty wire. A few weeks later the problem came back however it's at random. Hitting pot holes and hard breaking doesn't seem to affect when or where it turns on. I don't believe it's a faulty signal either as when the light turns on I can actively see the batter gage begin to drop.New battery and the side mounted terminals are tight as well. I believe it's still a wiring issue however I am absolutely clueless on where to look. If anyone can point me in the right direction I would appreciate it and give updates on progress. Thanks
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
8,197
Tampa Bay Area
Visit THESE Links on the GMT Nation On-Topic Threads about "Parasitic Drain" ...and disregard the various Makes & Models of the various vehicles ...as... The Principles and Procedures for Diagnosis are what you are after here:

 

Kgurn1020

Original poster
Member
Mar 2, 2023
43
Massachusetts
Visit THESE Links on the GMT Nation On-Topic Threads about "Parasitic Drain" ...and disregard the various Makes & Models of the various vehicles ...as... The Principles and Procedures for Diagnosis are what you are after here:

Thank you I will look more into it possibly being a parasitic drain. However it doesn't seem to be slowly losing power, as the battery light comes on and shuts off at random, giving the "battery not charging" warning. seems to me possibly a loose connection between the alternator and battery somewhere. I wiggled the wire repair the shop said was the culprit and nothing changed. I also tugged on the positive cable running to the red auxiliary power box between the alternator and battery. Just drove 60 miles to and from work with zero issues but if I want to run to the store at 8pm it'll pop on. Driving me insane
 

Mooseman

Moderator
Dec 4, 2011
26,016
Ottawa, ON
Getting the message "battery not charging" is very specific. The PCM is not detecting the alternator working. Of course the grounds should all beck checked and cleaned. Another thing that should be checked is the fuse box, both topside and bottom. Check fuses for proper connection in their slots as I have seen fuse legs become corroded with green pus in those trucks. Pull each fuse and spray some contact cleaner or DEOXIT. And when reinserting the fuse, check how much resistance the fuse is giving to being reinserted as this could be an indicator of loose connectors in the fuse box. On the underside, check for broken copper traces.
 

Kgurn1020

Original poster
Member
Mar 2, 2023
43
Massachusetts
i believe I solved the issue, I had noticed that at the little red junction box that ties into the alternator and the positive terminal wire, there was a slight spark when wiggled. I wire brushed all open ends of the positive cable, then put dielectric grease on the open ends, hoping to isolate the connections. I did this about 2 months ago and it has not come back since. Thank you for everyone who responded I will let you know if the issue comes back
 

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