Voltage regulator replacement

Tiny
JESSH
  • MEMBER
  • 1994 JEEP CHEROKEE
( Grand) 130,000 miles six cylinder two wheel drive automatic.

The voltage regulator in my vehicle seems to have gone out. Unfortunately it is built into the PCM which would be pricey to replace. I have been told that I can use a standalone voltage regulator from another vehicle. I assume that I would just need to connect the voltage regulator to the field terminals and power but I would like some advice before attempting the transplant.

What voltage regulator should I use? Would ones made for any particular cars be a better bet?

Am I correct in assuming that this will work and that it will only require hooking up a few wires and figuring out how to mount it?

Any other advice?

Thanks,
Jess
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Wednesday, February 7th, 2007 AT 1:26 PM

4 Replies

Tiny
JEEPMAN12345
  • MEMBER
Hello,

Yes the PCM does regulate the voltage so you can wire in an external one I suggest from a 1985 chrysler product there are easy to wire in. Here is the wiring diagram to help you.

Check out the diagrams (Below)

Please let us know if you need anything else to get the problem fixed.

Cheers
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Wednesday, July 14th, 2010 AT 11:45 PM
Tiny
KAZAM
  • MEMBER
I agree with the response by jeepman12345 because I have a 1991 Jeep Cherokee with an external voltage regulator (the type described by JessH (built into the power-train control module under the hood), in fact there is a site that sells conversion kits for wiring in an aftermarket external regulator:here is one:
http://www.2carpros.com/topics/electrical/alternator
Also, I believe, due to experience, that buying parts from a scrap yard or recycler is fine so long as they are checked, even though a warrantied part may be right/better for Some circumstances.
Also, if the alternator on JessH's Jeep truly is the external type then it could be identified (for clarity) easily by the casing design.
http://www.2carpros.com/makes/jeep/grand-cherokee

K. Shah
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Monday, December 27th, 2010 AT 6:09 AM
Tiny
JEEPMAN12345
  • MEMBER
Okay kazam, the voltage regulator is in the ECU, but before you change the ECU check the engine fuse box and check the 50 amp alternator fuse before you spend $109.00 on a ECU or $60.00 on alternator trust me I had the same problem before. Do not go buy a external regulator like KAZAM is telling you to do that a really bad idea. If you need a new ECU it take forty five minutes to put in and you can get one for $109.00 on eBay used that is plug and play or you can get a new one with a life-time warranty for $175.00 and do not buy from a junk yard like KAZAM is saying because you then have to bring it to a dealership and pay $200.00 to get it programmed. If in fact you do need a ECU not PCM you want to get a plug and play so all you have to do is pop it in and your ready to go. But before you do any of that check you alternator fuses and that not the problem get a jumper cable and see if it a grounding problem. Trust check these things out, because I had a guy come into my shop one because he kept replacing things and could not fix the problem he change the alternator three times bought a new ECU and still had a voltage problem so he took his car into me and I look at the two (alternator) fuses and there where blowing out. The poor guy spent $250.00 replacing things that did not need replacing so again check your alternator fuse in the engine. By the way you should go pick your self up a Haynes manual.
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Wednesday, December 29th, 2010 AT 5:57 PM
Tiny
KAZAM
  • MEMBER
01-03-2011
Greetings,
jeepman12345 I never did "tell" or tell anyone to buy anything or make any system changes. I did provide additional options to enhance a posting with a somewhat blind field of sight; watch your facts.
Also, I have to add that the Jeep alternator fuse I have most often seen is a 60 amp rather than a 50 amp (though I am not saying that a 50 amp would be out of the question always).
I did say that junkyard parts are alright if they are correctly tested; many of the parts on eBay are from junkyards, tested or not. Either way it is important to check the parts or have a warranty before purchase; too, even with some warranty, it is something to consider that eBay transactions have 'eaten-up' very much money with shipping costs due to returning parts.
And, the PCM is under the hood, I do believe that is where the alternator wiring does lead to. The ECU is inside the cabin, under the dash area. I do not think the alternator is wired straight to there. I will revise this statement if my research (in the factory manual ) indicates otherwise.
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Tuesday, January 4th, 2011 AT 12:31 AM

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