MY BIG MYSTERY-14.5 volts on first start.12.5 volts next start

Really strange thing, when I start the car and battery light doesn’t come on, then I count to 10 seconds, turn off and back on and repeat light doesn’t come on. Almost a rhythmic thing. Like it’s depends on where the belt and or alternator stops in it’s rotation​:thinking::thinking:

That’s a pretty good choice for the replacement alternator. Could still be problematic right out of the box, but much less likely given the AC Delco branding. No way to tell other than testing it. Or trying a known-good one. The only other thing I can think of re the alternator, alternators come w/ different power (amp) ratings, perhaps the replacement isn’t meeting your car’s amperage requirements.

Regarding why it works one time, not the next. A shop might be able measure if the field current signal is lacking when it doesn’t work. Alternators have fix windings in the non-rotating part that capture the induced current from the rotating part’s magnetic field. The alternator’s rotating part is an electro-magnet, supplied with a field current proportional to how much output current is required. I suspect that’s the problem, no field current. Of course you’d still be at square one, but at least you’d know to focus on why there’s no field current.

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Good afternoon everyone,

So after many blood,sweat,tears,money and troubleshooting, I sent back my remanufactured alternator and bought a new OEM one. PROBLEM SOLVED!!! Either Amazon matched my car up with the wrong one or it showed up broke. Moral of the story, buy brand new for key/hard to install parts!

Thank you for all your inputs!!!

Michael

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