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Discussion Starter · #1 ·
Ok so i bought a brand new battery and i put it in yesterday and drove the truck all day. Unplugged the positive cable overnight because i was under the assumption i had a drain somewhere because i killed an optima red top. it was about -7 over night and the brand new HD 950 cca farm implement battery was dead as a door nail. I thought I maybe got a bad battery. Lucky me. So I took it back to the auto parts store and they tested it and said it was good. They charged it up for me and said to bring the truck their with the battery in it and they would test the alternator, starter, and charging system. Turns out the alternator was not charging the battery and while the truck was running it was pulling all of the power from the battery. I had just replaced the whole engine wiring harness with one from a 92 and since dodge changed the charging system to and internal voltage regulator in 92 i had to wire mine in. If i had wired mine in incorrectly could that be the problem. Also could I have simply missed plug somewhere when installing the new harness because the alternator was fine before hand.
 

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OK I know your Problem first off just went through this on a truck I am trying to fix .You have to Change both harnesses under hood and under dash and also you have to put a Crank possition sensor on front of Motor the charging system does not see the cps so it does not tell the computer to turn the charging system on the 91.5 harnes is Different in cab . and if your auto you have to change the trans harness also because it's part of the CPS harness . 91.5 does not have a CPS sensor on front of motor like the 92-93 does have any more question's let me know .
 

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Discussion Starter · #3 ·
So your saying I have to change the harnesses again because I don't want to do that nor do I have the time or money. What is a cps and why can't I just change the way mine is
 

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You have to change the trans harness and you have to Install a crank position sensor on front of motor like the 92-93 truck's have that way the computer will tell the Alt to charge when the key is turned on . And Also so your Auto trans will have overdrive .it need's the sensor so it knows when the truck is Moving . I am fighting the same thing .also on the 91.5 truck I have . Question did you change the under dash harness ? if not they are Not the Same and will not read eachother .
 

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Discussion Starter · #5 ·
Well it has worked fine so far. OD has worked great and all in cab functions are the same. Why does the trans harness need to be changed? Where do I get a cps and how do I mount it
 

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Just put a external regulator on it and call it a day
 
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Discussion Starter · #7 ·
I did that is where I think the problem is. I may have wired it incorrectly. What does the external voltage regulator do exactly
 

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It eliminates the regulator in the ECM and does it the old reliable way.

FAQ Do it like this just be sure to remove the 2 small wires already there that goes to the ECM. The Case of the regulator has to be grounded good.
 

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Discussion Starter · #9 ·
Ok thanks….
 

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Discussion Starter · #10 ·
ok well it still isn't happening…bought a new regulator and nothing….is a 92 alternator different….does it read from the internal regulator could i just put a 92/93 alternator on and call it a day and remove the external regulator or can somebody give me a diagram on how to wire in an external
 

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As far as I know the 1 and 2nd gen alternators are all the same, maybe just different amps.

FAQ Here is how to wire in a external regulator, make sure the metal case of the regulator is grounded.

You will not be using the 2 small wires on the back of the alternator they will have to be replaced with new wires to the regulator.
 

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No internal regulators on stock Mopars, either the old style box on the firewall or inside the computer.
 

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Discussion Starter · #13 ·
ok well i found the problem…one of the terminals on the back of the alternator was snapped clean off…bought a new one gonna put it on tonight probably
 

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Well at least it was a easy fix, thanks for letting us know what the problem was. I've heard of that happening before.
 

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Discussion Starter · #16 ·
ya easy fix but not easy on the wallet….parts are so expensive these days
 
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