This could be an issue with the battery, but we need to start with checking the basics so that we are not chasing our tail.
This means we need to start with checking the alternator and battery as shown in these guides:
Even though the alternator is new, we still need to check it because new parts can be faulty as well.
Then we need to check the voltage at the alternator and find out what is there.
Basically, we could have a PCM issue as this is the field control, but we need to start with this and go from there.
Please see the wiring diagram below for more info and let us know what you find. Thanks
Tuesday, November 2nd, 2021 AT 1:34 PM