92 Cherokee; voltage regulator question.

dptyrob

dptyrob

Well-Known Member
Joined
Jan 29, 2006
Location
Clyde, NC (Haywood Co)
Hello all. I just picked up my old man's 92 Cherokee with 4.0. There is a problem with the alternator charging. It appears to just charge whenever the mood strikes it. The guy at the parts store told my old man that the voltage regulator is built into the ECU, however I looked up a rebuilt kit on Advance Auto Parts web site and it listed a voltage regulator with the kit.

So, is the voltage regulator in the alternator or in the ECU on this thing? I've read where some jeeps do use the ECU. I just don't wantto spring for rebuilding or replacing the alternator and that not turn out to be the problem.

Thanks.
 
It's been my experience that the volt reg is in the alt. To be sure, remove the alt and take it to Advance or Auto Zone where they will check it for free.
 
Yeah, I've always seen the ones that are either inside the alternator or outside of it in the engine compartment somewhere. But this yahoo at the parts store said something about the ECU and I found something about some TJ's using the ECU on another board, so I thought I'd double check before I grab an alternator.

Thanks.
 
i've been having similar problems with my 97 tj. took out the alternator, had it tested--it tested good, then put it back in and it's been working for now. with the tj the voltage regulator is an integrated circuit in the pcm. i just figure that unhooking the battery when i took alternator out reset it and fixed the problem but we'll see if i start having problems again.
 
Well, as it turns out the voltage regulator is in the ECU on this Cherokee after all. However, the intermittent charging was apparently due to worn out brushes, not the voltage regulator. The guy at the shop where I took it popped it apart and showed me where one brush had a dull finish and the other one was shiny. He said it would probably arc enough to charge every now and again if you hit a bump just right. He stuck a set of brushes in and we're as good as new.

On a side note, he told me that if the voltage regulator was a problem that he could "piggyback" one into the wiring for me; that it might cause the CEL to stay on, but that it would work just fine. Definitely something I intend to keep in mind for future reference.
 
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