Alternator not charging, but tests good. Do I replace? 2008 Sequoia - 386,000 miles.

A couple of months ago, I was driving and my voltmeter dropped and the batter light came on. It was only a few minutes and then went back to normal. This happened a dozen times since, only for a few minutes. I figured the alternator was going bad, it has 386,000 miles on it.

Yesterday driving at 60 mph, the battery light came on, the gauge read low voltage and all the electronics in the sequoia stopped working, even the hazard flashers. I was stranded, so my son came and jumped me off, it ran for 2 miles on the highway and the same thing happened again. So he towed me home with his 2004 Tundra. He was proud of that.

Today, I pulled the alternator and took it to Autozone to get a replacement. Just on a whim, I asked them to check it to see if it was bad. The machine tests that the alternator is good.

What do I need to look at now?

I'm about to put the alternator back on since it doesn't appear to be in bad shape, and it tests good. The store recommended that I check the wiring to see if it's a short somewhere, but I did that and can't see anything wrong.

Any suggestions are appreciated.

 

Could be worn out brushes in the alternator, that are barely making contact now that the alternator has been disturbed and bumped around a bit.

 

From the jump and 2 miles routine, sounds as if the battery works. I'd inspect (ohmmeter / test light both sides) the fuses in the charging circuit first. If those all test out good. I'd replace that alt and see. If the new one does the same. it is indeed the charging circuit. You would have to start detailed inspection of it to find the break.

 

Well, i put the old alternator back in the truck. If it ain’t broke don’t fix it. Replaced the serpentine belt and did a very close inspection of the charge cable. Found an intermittent short where the cable connects to the positive battery cable just before the battery connection. That appears to be the culprit.

Now, I have another issue with the electrical connection to the power steering pump, I broke it off when reinstalling the pump and now I have a power steering red light in my instrument cluster.
Anyone know if that can be repaired without replacing the whole pump?