Hi! New guy here. My boy has an ‘03 Grand Cherokee, 4.0 inline six… started with intermittent charging while running. New battery, seems to stay up when not running. Alt checked good by two different places. Terminals and grounds seem to be good. Unhooked big hot from alt, not charging when running. Disconnected field terminal connector. Had batt charger hooked up to boost start. Checked volts at the field terminal connector at about 10.6 vdc with the charger still on. Turned charger off, still running, and connector volts dropped to about 6 vdc and change. Big hot was discoed at this point.
My next step is to try to introduce 12 v to the field terminal to see if I can get an alt output. Thinking maaaybe I need an external voltage regulator? Thoughts please? Thanks!

 

Well, just in case this helps someone… alt was tested twice good at autozone, and once good at oreillys… it was bad. Had it rebuilt, and everything is working great… Den