Hi,
I have a 2016 JKU Willys with 162K on it that had the starter die. I swapped that and realized I had a battery issue too (tested low, all the lights in the dash came on), so I swapped the battery. After that the battery light came on again and when testing I was getting 12.2-123 volts at the battery, but 14.5 coming off the alternator. I did find a frayed ground strap by the PCM, so swapped that too.

Still not charging and the battery light comes on after about 30 seconds ( the ABS and Traction co from are on as well).

I have absolutely no idea what the issue may be.

any ideas?

 

The alternator is connected directly to the battery with 4-gauge wire. If you are reading 14.5 vdc at the alternator, you should read 14.5 vdc at the positive battery terminal.

1) Could be a break in the wire between the alternator and the battery. Disconnect the battery negative terminal, then the positive terminal, and use an ohmmeter to measure continuity between the alternator positive terminal and the positive end of the wire at the battery. Should read zero ohms.
2) If you used different grounding locations for measuring the voltage, it could be a grounding issue. Check the main ground from the battery to the engine block. That should also be a 4-gauge wire. The alternator is grounded by its mounts to the engine block.

Good luck!