I just replaced my alternator but my car voltage is reading low there’s no battery light but my voltage meter reads 11.6 V when I turn stuff on it will read even lower try to do the test where are you disconnect the negative with the car still running the car still runs but only at 8 V it’s a brand new alternator can’t figure out why it’s not charging
First things first: Particularly with aftermarket goods, new is not the same as known good.
Second possibility: The clamps or harness to the battery terminals are bad, or the clamps are loose or dirty.
Third possibility: Check fuses, as well, for power/ground, starting with the fuse to the alternator.
The alternator is an Ultima from O’Reillys all the fuses that I can see are good that are connected to the charging system the one ground I found looks OK I’m just wondering why is it only putting out 8 V
As for the fuses: Does "looking OK" mean that you've tested them with a probe? Or is it just a visual inspection?
If you've tested these and they are OK, then either the serpentine belt is not routed correctly or the remanufactured alternator is defective.
Check all of your wiring connections and the belt. If all of those are alright, you may have a defective alternator.
didn't mention what vehicle it's for: make, model, engine? Is the belt routed properly and tight? Also, you could've got a bad one, bring it back to O'reillys, it happens.
