Alternator Regulator Is Bad?

I put a question mark on the title because I'm completely ignorant about things electrical. I'm posting for a friend who just acquired a stock 2000 XJ from a family member. He says his uncle told him that the alternator regulator is bad and he bypassed something (forgive me, I forget what was bypassed). The Jeep runs, there seems to be no ill effects, but my friend wants to learn more about this and see if he can fix this without spending the $400 that his uncle said it would cost to fix.

Can anyone shed some light on this .... even though I might have totally messed up the question?

The regulator for the alternator is part of the PCM (computer) if it goes bad, and it is known to go bad charging issues would result. It could be restored by replacing the PCM with a good one. The other option is one of these,...

https://alternatorparts.com/external-voltage-regulator-high-output-alternator-kit.html

I have used one before and liked the ability to adjust the charging voltage via a potentiometer. I have since resorted to the PCM controlled unit and like it better than the after market unit.

What is the Jeep doing? You stated that it an fine. Is it not charging? If so how was this verified (professional meter or vehicle instrumentation)?

As far as I know the Jeep is doing nothing out of the ordinary. I've never even seen the vehicle. But my friend was concerned about the information he was given by his relative, especially since it concerned the computer. He's a pretty young dude and never owned a Jeep before (poor guy!). I'll pass the question on to him tomorrow and see what he says. For all I know, the Jeep might already have that external voltage regulator referenced by techno1154 - and thanks for that link techno. Never knew such a thing existed!

Sounds like his uncle didn't want to spend the $400 to replace the PCM if the story is correct.
If they used a kit, or did a good job bypassing the PCM your friend can leave it or fix it. If it functioning properly I'd leave it for now. Especially if it's a novice doing the repairs. Not putting anybody down, I remember the trouble I had learning with my first car, some problems are better left alone until they are necessary.


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Good advice. Thanks