Alternator won't charge when the car is started when warm.
What is your question?
When I start and drive it from a "cold" start, the alternator charges as expected; the voltage gage shows in the 14.5v range. When I shut it off and start it back up while still warm (like at a gas station) the volt meter shows around 12v with the battery light on indicating no charge.
Here's what I did so far:
Replaced the alternator (it was old anyway but the problem remains with the new one)- I will take this new one out (it's a remanu) a try a different one.
Replaced the ECM/PCM but still there (seems to run better, oddly enough)
Checked all the grounds - fine
Checked power directly from the alternator both hot and cold: shows the same results as the volt gage.
Checked power at battery, same as volt gage.
Tried different batteries: same result
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I seem to remember some GM`s having a ground problem with the alternator bracket to motor connection.Get a jumper wire heavy gauge or jumper cables a supply a ground from the battery negative to the new alternator body.If it helps you have a poor ground issue.
Wow, this is a zombie thread! As it turned out, the replacement alternator was actually defective. I don’t know what the odds of that happening are but when I took the “new” (remanufactured) replacement alternator back, the store tested it and it was indeed defective.
Short story, the alternators on those trucks have a life expectancy of 80k give or take 20k.
They gave me a new alternator and that fixed the issue.
Just tried that, no dice. I'll take this alternator back to the store. That's the only thing I can think of, and I doubt that is the problem.
Don’t know if you’ll get this thread but I’ve got a 2003 s10 with the same issue can you tell me what you did to fix it if you could
Wow, this is a zombie thread! As it turned out, the replacement alternator was actually defective. I don’t know what the odds of that happening are but when I took the “new” (remanufactured) replacement alternator back, the store tested it and it was indeed defective. Short story, the alternators on those trucks have a life expectancy of 80k give or take 20k. They gave me a new alternator and that fixed the issue.