2001, 4.6, RWD
My battery light came on. gauge still showing just above halfway. Put a meter on it, 12.1V, didn't go up when reving engine.
Is there a voltage regulator, or is that in the alternator? Anything other than alternator that might cause this?
Thanks

 

The regulator is built into the back of the alternator. The brush package is also under the regulator. The brushes tend to cut into the wheel and can cause what you are describing. You are better off with a reman'd alternator replacement.

 

Ize not a fan of reman alternators, unless you reman it youself. Seen quite a few didnt work right out of box. I think some are fixed, not remaned, and look a like similar old parts get mixed and reused.

Ive had great luck with new ones from parts stores. Never had one fail.

 

I rebuilt two of them awhile back. They're not hard to do if you're somewhat mechanically inclined. If not, I'd suggest you seek out a local reman shop to have yours rebuilt rather than gambling on an Advanced AutozO'rileys unit, assuming you can get by without the truck for a day or two.

 

Somewhat related note... I brought an alternator from my parts truck to O'Reilly's to have tested and they failed it. Then went a few doors down to NAPA and it passed - twice!

Don't rely on those free alternator tests (unless it passes of course

 

I have a good starter and alternator shop here and I always just have those parts rebuilt. If I need a starter or alternator tested, that's where I take it, not a parts store, because they are not that accurate.

 

Sorry it took me so long for an update.
I replaced the alternator with a reman unit, been working fine.
Thanks for the help all

 

Thanks for following up with your outcome/results. Lots of threads end up with lots of suggestions and assistance, but never any resolution.