I have a 2003 Tribute v6, approx 85K miles rebuilt engine, etc. Over the last few months, when I first start the car and/or within maybe the first couple of miles driving, the battery light on the dash may come on for a few seconds but then goes back off. If I'm driving it may stay on for 15-20 seconds occasionally, and it may do this a couple of times before finally going off and not happening again that day.
It's like once it's happened I'm good until the next day, or a few days..sometimes it can be a couple of days without it happening at all. Then it will happen again. Below are some things I've noted...it's interesting, but I'd like to fix it.

I hooked up a voltage meter to the battery with the car off, and it gets a solid 12.5v (fairly newish battery.) With the car running, I tested the cables at the battery and get a fairly consistent 14v (+- a few volts if I gas it or kick on the A/C). I even tested with the battery cables disconnected and it all ran fine. So...

Today I hooked up the voltage meter again at the battery cables and set it so I could watch it when I first started the car. I got the usual 14v, and as I watched the dash I saw the battery light come on for a few seconds. But the voltage did not change at all while the battery light was on, or once it went back off. It was only on a few seconds, might have done it twice a few seconds apart, but then didn't come on again. Still, the voltage at the battery posts/cable stayed right at v14 and didn't budge or waiver at all.

That makes me think some quirky something other than the battery or alternator is causing the light to come on. At least I feel more confident that it's not a drop from the alternator itself.

So, anyone know what might cause the light to come on like this?
Thanks..

 

These vehicle are notorious for the power cable connection on the alternator to corrode & burnout.

Something for you to check.