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  • W-T ground wire mod - Simplified

       (5 reviews)

    Ok I know several members have done this mod and said it was easy. It sure is easy. It takes about 2 hours from start to finish to complete this project. You'll need the terminal lugs and the metric bolt that @W-T specifies in his article. 

     

    First thing disconnect your batteries. I unhooked the two negative leads. 

     

    You need to gain access to the loom going across the front of the engine. So you'll need to remove the upper alternator bracket and the the two loom holders on the front of the block. I did this during my coolant flush project so my upper hose and thermostat are removed. If you have my crankcase vent that will need to be removed as well.DSCF4411.JPG

     

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    Now I started at the battery and the alternator and started unhooking the wiring from these devices bring it forward.

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    Now you start working on getting the split loom off the wiring. Start at the tape with a small exacto knife or razor blade and carefully split the tape to release the plastic split loom cover. Carefully remove it. I found out mine was brittle after all the years of engine heat. Once you remove all that slpit loom you can again split the spiral tape holding the loom together.

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    Now you show be able to have both the ground lead and the alternator charge lead loose now. I will admit the alternator lead took a bit of work to release at the knot of tape on mine where it breaks out of the loom heading for the PDC. Just take your time with your razor blade and your get it released. You can clearly see the splice of the ground just like @W-T mentions in his article. 

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    Once you get the alternator lead out in one piece. Then the ground lead I used a pair of wire dikes and cut the ground right at the end of the splice. Now the alternator lead I reused the wire since it was in excellent condition. I mocked up the alternator lead by hooking it back up to the alternator like it should be and gave it a nice loop of slack then cut it to meet the positive battery terminal. 

     

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    On my terminal lugs, I took a hacksaw and scored the plastic collars and peeled them off for soldering. Then slipped the lug on and used a propane torch with the low flame and soldered the lugs right on to the wire. Good sold weld and this will seal the wire from future rot from battery acid and vapors.

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    This is the completed alternator connection now. All I did was grab an old nut and stacked on the battery terminal.

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    Now we are going to do the ground side. Now trim back the old splice and free the ends of the wires. Now strip back the wire so you can fit the wires into a lug. Again I did the same thing I took the hacksaw scored the plastic collar and peeled it off the lug and then slipped it on the wires and prepped it for soldering.  

     

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    Again just slipped the lug on the wires and low flame with a propane torch I soldered the lug to the wires. 

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    Now I cut the old plug off the splice on the passenger side ground and then trimmed the length of the wire with the plug so it would reach between the driver side battery and the gear case. Same again I peeled the plastic collar and slipped the lugs on and soldered with low flame propane torch.

     

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    This gives you an idea where the wires go. Take your metric bolt and attach the ground wires to the case. Then the ground cable to the negative battery terminal on the driver side. 

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    Beyond this is just clean up. Now you need to tape up your loom again. I'm going to replace my split loom with a smaller size being the old loom was brittle and was breaking during removal. The only thing that should run across the front of the engine now should be the ECT sensor which is a twisted pair. The A/C compressor, A/C high-pressure switch, and the alternator field lead.

     

    Before AC noise level was 0.038 AC volts now after the mod its dropped to 0.015 AC volts (or 15mV AC).

    About the parallel cables...

    There is lot of folks being told they NEED the parallel the positive and negative cables. To test if you need that or not. Take a good quality DVM meter capable of DC mV scale. Now place a Black probe on the battery terminal and the red probe on the block (clean metal). Typically I see 3mV (0.003 volts) after doing the other part of the ground wire mod. Now take a set of jumper cables and go from the negative post to negative post. Also check the AC noise voltage with the jumper cable hooked up if there is no real change then you do not require the parallel cables. If the voltage drop is the same with the jump cables then you do not require the parallel cables because there are ZERO improvements. You can do this on the positive side as well. If there is a voltage change my first thought is to replace the BAD cables first before paralleling on a bad cable. All you do is covering up a bad connection. Adding the extra cables will not improve anything if it's not changing the voltage drop from point to point. 

     

    Addon: Protection fuse or fusible link

    Some members are suggesting to install a fusible link or fuse of the same size at 140 Amps on the charge lead as a protection method. Just in case for some reason the diode bridge happens to short the positive side to the ground and doesn't start an engine fire.  As for the size of the fusible link is still unknown as of yet. The factory is 140 amp fuse. The fusible link would be better suited than a fuse. 

     

    I've found a few trucks that is incapable of doing a circuit breaker because of mystery loads and causing the breaker to trip prematurely. Fuse will solve this problem but make sure to carry an extra fuse. 

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    OmahaGen2

    · Edited by JAG1

       4 of 4 members found this review helpful 4 / 4 members

    As Always thank you (and everyone) for taking the time to document, taking pictures and sharing.. .I could not afford this truck without the information I have gained from this forum & that's a fact.

    So about this modification, I am not sure where I missed it, so just to clarify, the alternator lead going across the motor to the PDC is eliminated.  In it's place we will have: A. Alternator charge lead from the alternator to passenger battery..  B. A power lead from the drivers side battery to the PDC.  

    (The grounds I believe I have correct & will be done with all in about an hour)  Electrical is my Achilles heel .......LOL  I 

     

    ON EDIT;  once the B+ charge wire from the alternator is moved  the shorter distance to the passenger battery, a great solution, but you lose temperature battery sensing with the sensor still on the drivers battery. You can either move the sensor over to the other battery, with some modification, or run more parallel cables battery to battery. It will need two more heavy cable negative to negative and one more heavy positive to positive. My solution is to run one longer B+ charging cable to the drivers side battery. Without the battery temperature sensing feature on an old battery that develops a shorted cell will cause the PCM to keep charging the battery at full tilt. The alternator will get smokin' hot and can cause damage. Luckily I got home before any real damage to the PCM or other possibility of a fire. I popped the hood , knowing something was wrong and the alternator was so hot it was smokin. You couldn't touch it. I replaced it and both batteries and all was fine. I did notice where the shrink tubing on the charge wire started to melt as well. I'm glad I caught it when I did.

     

    AN IMPORTANT UPDATE:  A recent conversation with Billy (W-T) he spoke about the absolute importance of properly paralleling both batteries by adding one more positive to positive cable and two more negative to negative cables. This a much better solution than all other options so that the computer will be able to temperature sense what one bank of batteries need as one battery bank. Not having a situation of charging one battery while the other has the temperature sensor. IOW, they need to be properly paralleled as one battery. This very important factor has been eliminated from W-T's original write up, so I just wanted to bring this up.

    Response from the author:

    No need for the paralell battery cables. When checking voltage drop I had exactly 3mV drop from battery to block. Added jumper cables to both ground and then to the block again. 3mV drop still so adding the parallel cable will not improve anything. I've been testing even the other truck I've done this mod to and never could shave off that 1 to 3mV drop on the ground side.

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    DDD

       2 of 2 members found this review helpful 2 / 2 members

    Extremely helpful write up! Very well done! Just have a couple questions. The thick wire that runs from alternator to PDC is completely removed and replaced with a wire from alternator to positive battery terminal on passenger side battery correct? And then the wire that you had made up with the clip in the middle goes from ground terminal on driver side battery to where? Does it go to PDC or do I ground it the same place as the 4 other grounds that were exposed during this process? If does go to the other 4 grounds then do I have to also run a wire from negative termial on battery to PDC

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    Paul C.

       2 of 2 members found this review helpful 2 / 2 members

    This is awesome, I surely appreciate every bit of information I have read so far on here.

    I have a 24 valve in a 1997 Kenworth service truck, and I have been chasing an intermittent dead pedal issue and while I'm working on it decided to take care of some ratty wiring that I have found since owning the truck  !

     

    Thanks for the knowledge 

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    trailhead

       2 of 2 members found this review helpful 2 / 2 members

    This article is incredibly well written and very valuable.  This site rocks!

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    ram fan

       2 of 2 members found this review helpful 2 / 2 members

    first of all I'm new to the forum and still figuring out how to navigate through this stuff. the explanation and details of my situation is outstanding, I love the pictures and the step-by-step very helpful thank you very much

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