I had been struggling with my alternator not charging for a few months and finally determined it was the ECM. Long story short, I replaced the coil rail on my 2002 and didn't have the 6th plug boot on correctly and it arced and shorted the voltage regulator in the ECM. I found this thread and ended up ordering a replacement from Mark at Wranglerfix. He personally answered the phone while on a test drive, took my number, then called me back within 30 minutes. He was very familiar with my ECM and the issue. The ECM arrived in a couple of days and is working fine so far. Everything is back to normal and no check engine light. I am probably going to send my old to him to get fixed and keep it as a spare.