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Unread 02-12-2011, 08:31 PM   #1
ledrefoc
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1996 XJ Cherokee 
 
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External Voltage Regulator Help ASAP!!

recently my xj died while driving, after cleaning all connections, grounds etc, new battery, and new alternator, im coming to the conclusion that the voltage regulator in the PCM is no longer working, and since i dont have $250 to drop on a new computer i am going to bypass it and install an external voltage regulator. I have already purchased the regulator (pt #VR733, from 85 dodge pick up) and have the plug. Now my question is where do u tie the two wires from the plug into on the alternator? Has anyone else done this? pictures would be very helpful. Need to get this going ASAP! Have to drive it to work on monday!! THANKS!

ps its a 96 XJ country

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Unread 02-12-2011, 09:01 PM   #2
Holder350
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The PCM dieing and screwing up your VR is very rare....

Have you swapped the Alt and still have the problem?

High running voltage points to a VR problem, LOW running voltage usually points to a failing diode bridge.

If you do have a problem with the PCM voltage regulator....then I can tell you how to wire up the 2 wire dodge regulator and make it work.
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95' XJ Country - Stock Skids - D30/D35 Limited Slip - 3" Lift - 31x10.50R15 - 4.0 HO - AX15 - NP231

98' XJ Classic - D30/C8.25 - 4.5" RC Lift - 33x12.50R15 - 4.0 HO - AW4 - NP231
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Unread 02-12-2011, 09:21 PM   #3
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You will have 2 small wires connected to your alternator, these go to the field coil.

One of these will have a 12v ignition source on it (to a local ground not the other wire, should be a Dark Green/Orange wire)

The other will be the return to the PCM control circuit. (should be a Dark Green wire)

You need to splice into the DG/OR 12v wire and run it to the IGN terminal on the regulator. (Do not disconnect this wire from the alt, as it will feed the field coils with positive voltage)

The DG other wire, you will need to cut and connect to the FIELD terminal on the regulator, then mount the regulator to a good local ground.
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95' XJ Country - Stock Skids - D30/D35 Limited Slip - 3" Lift - 31x10.50R15 - 4.0 HO - AX15 - NP231

98' XJ Classic - D30/C8.25 - 4.5" RC Lift - 33x12.50R15 - 4.0 HO - AW4 - NP231
Quote:
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You can tell the character of a person in how they treat someone who can do nothing for them.
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Unread 02-12-2011, 09:22 PM   #4
ledrefoc
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yes i have new alternator, and new battery, i would love to know how to wire up the 2 wire regulator! even if it was just as a temp fix.
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Unread 02-12-2011, 09:35 PM   #5
Holder350
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Heres a little more visual help


I dont know which field terminals are which, doesn't really matter you just need to find your 12v switched source.
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95' XJ Country - Stock Skids - D30/D35 Limited Slip - 3" Lift - 31x10.50R15 - 4.0 HO - AX15 - NP231

98' XJ Classic - D30/C8.25 - 4.5" RC Lift - 33x12.50R15 - 4.0 HO - AW4 - NP231
Quote:
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You can tell the character of a person in how they treat someone who can do nothing for them.
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Unread 02-12-2011, 09:37 PM   #6
ledrefoc
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ok this is what im looking at...looks like someone else has been in here before, dont mind the red and black wire they are my 'uneducated' guess at this hook up for the regulator. now which is the green/orange
dsc_0967.jpg  
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Unread 02-12-2011, 09:41 PM   #7
Holder350
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well....hmm...dont know....but all you really need to do is find the one with 12v switched voltage...thats the one you want to tap and the other you can cut and splice.

A test light and ohm meter come in really handy.
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95' XJ Country - Stock Skids - D30/D35 Limited Slip - 3" Lift - 31x10.50R15 - 4.0 HO - AX15 - NP231

98' XJ Classic - D30/C8.25 - 4.5" RC Lift - 33x12.50R15 - 4.0 HO - AW4 - NP231
Quote:
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You can tell the character of a person in how they treat someone who can do nothing for them.
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Unread 02-12-2011, 09:47 PM   #8
ledrefoc
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unfortunatly i dont have one here at home. but wow THAT is EXACTLY what i needed! Thanks ALOT!! seriously, you're the man!
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Unread 02-12-2011, 09:48 PM   #9
jrb94zj
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I just want to make sure I understand. It will start with the battery charged and run until the battery no longer has enough juice? Or it doesn't run at all?
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Unread 02-12-2011, 09:53 PM   #10
ledrefoc
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it will run right now but as soon as the battery drains its dead. i know i probably shouldnt but i removed the battery cable from the battery while running and it shut off immediately leading me to believe its the alternator however, the alternator is new. and after what ive researched looks to be that some people have been having this same issue and it was the voltage regulator/pcm, if i had a spare pcm to change out that would be the best way to find out if it is in fact the pcm. but i dont have a spare lying around. i couldnt imagine what else it could be since everything is new, no blown fuses, and the grounds and connections have been cleaned
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Unread 02-12-2011, 09:56 PM   #11
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Just looked thru the FSM, found that your 12v should be the terminal closest to the ground screw (the terminal your red wiring is going to)

And the PCM driver, (the wire you need to disconnect) is the other terminal (black wire)

If you have 12v on the right terminal to ground, but nothing to the other terminal, you can just use your extra wires you have already added to connect your regulator.
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95' XJ Country - Stock Skids - D30/D35 Limited Slip - 3" Lift - 31x10.50R15 - 4.0 HO - AX15 - NP231

98' XJ Classic - D30/C8.25 - 4.5" RC Lift - 33x12.50R15 - 4.0 HO - AW4 - NP231
Quote:
Originally Posted by Azzy View Post
You can tell the character of a person in how they treat someone who can do nothing for them.
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Unread 02-12-2011, 10:15 PM   #12
ledrefoc
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VERY MUCH APPRECIATED I will let you know how it turns out THANKS for all the help!!
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Unread 02-12-2011, 10:37 PM   #13
ledrefoc
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ok before i go cutting wires.... the red wire in my picture is the wire running to the ignition terminal , and the black wire is running to the field the regulator is bolted on with a ground, now tell me if im wrong but if i just cut the dark green wire (not the DG/OR wire) then that should be correct right? or is it necessary to "splice" it?
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Unread 02-12-2011, 11:32 PM   #14
ledrefoc
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well instead of cutting wires i bent the prong on the connection out of the way and taped it up. however it seems that its still not working properly......after starting, the jeep should be able to run off the alternator correct? its not. im not getting a check engine light, battery light or anything... i suppose ill take the new alternator back off tomorrow and go have it tested.... any other ideas you may have come with them. im stumped and dont have the money to take it in somewhere or get something else.....
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Unread 02-13-2011, 07:04 AM   #15
Holder350
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The jeep will not run on just the alt, hell it wont run with a bad battery that puts out less than 12v...even if the alt is working.

I would check my running voltage at the battery and at the alternator.

If you dont have a VOM to check your voltage, then crank the motor and touch a screwdriver to the center of the backing plate. (the "bump" right above your field terminals) You should feel the screwdriver stick with magnetic force.

If it does, then the field wiring on the alt is working and it should be charging.

If not, then I doubt you have a good 12v source to the field, probably from a broken wire because it is on the same circuit as the ignition coil.
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95' XJ Country - Stock Skids - D30/D35 Limited Slip - 3" Lift - 31x10.50R15 - 4.0 HO - AX15 - NP231

98' XJ Classic - D30/C8.25 - 4.5" RC Lift - 33x12.50R15 - 4.0 HO - AW4 - NP231
Quote:
Originally Posted by Azzy View Post
You can tell the character of a person in how they treat someone who can do nothing for them.
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