Ground Reference VP44,ECM,PCM,PDC plus TC lock/unlock

[Billyshrieves]

I’m completely lost with all this I know the wire that’s coming off the alternator to the battery then to the fender but everything else I’m completely lost I’ve read all this multiple times I just ain’t no good with wiring period 

On 3/16/2018 at 11:28 AM, GSP7 said:

Can you guys post a link to the step by step rewire....

 

 

 

 

 

 

That’s what I’m waiting for is a step by step 

[dripley]

On page 2 there is s post by @IBMobile about 1/4 the way down with the cliff notes version. It is nothing but the steps. 

[rogerash0]

If this helps half of ya, it'll be a success. Never done a video before and I'm drinking that good 9% ipa so anyway maybe this video will help ya out.

 

https://youtu.be/MgtAT6CqR8s

[SilverMoose]

2 hours ago, rogerash0 said:

9% ipa

[buzzman]

I have been reading this thread over and over. I have the grounding side figured out, but I need clarification on the alternator charge wire. As shown in the attached photo, my 1998.5 has this junction block that hooks to the back of the alternator. I think it's different than the alternator connections on the 1999-2002 models. The block has the #4 awg charge wire, a #6 awg ground wire that runs a short distance to an engine block ground, and two #14 awg wires. I think I need to keep this junction block. So my questions are:

 

1. Do I just cut that #4 awg charge wire (the wire on the left in the picture) that goes through this junction block and eventually snakes it's way over to the PDC and 140 amp fuse and throw it away, therefore no more 140 amp fuse...and then run a new, much shorter, #4 awg wire directly to the passenger side battery positive terminal?

 

2. Should I add a fuse to that new #4 awg wire?

 

Many thanks to W-T, Mopar1973man, IBMobile, and others for describing this fix.

 

Buzz

 

 

[IBMobile]

Do the wires connect to the back of the alternator like this pictured below?   If so, cut the charging cable end (the cable that goes from the B+ alternator terminal to the battery) off and on the other side the rest of the cable that goes to the 140 amp fuse in the PDC.  That cable can be verified using an ohm meter testing from the 140 amp fuse to the alternator.  leave the rest of the wires connected to the alternator.  Now you can run the new cable from the B+ terminal to a fuse or circuit breaker then to the right battery positive terminal.

 

[W-T]

Buzz...I have not seen this before and I believe this is peculiar to the 98.5 platforms however; let me venture a guess. First of all the heavy 4 Gage is your B+ charge line and this will directly attache to the positive terminal of your passenger side battery. The two smaller 14 Gage lines are for "charge command" and will remain in their respective location along with routing within the plastic conduit. The 6 Gage routed to the engine block is an additional well thought out housing ground for the alternator. This is a nice feature that provides chassis ground for the alternator and avoids the possibility of a poor ground via the alternator mounting structure. This is something others and myself became aware of during the disassembly procedure as it becomes apparent the "mounting" is the critical ground for the alternator's chassis on the later run CTD's. I'm sure this was a cost savings adjustment for the manufacturer so view this as a plus feature of the 98.5 models. You'll find others who actually applied their own additional grounds from the alternator to the engine block due to corrosion of the factory alternator's mounting structure. It is a good prudent effort.

 

I believe @Mopar1973Man and @IBMobile may wish to confirm my educated guess...along with the fact that I have not been under the hood of a 98.5 CTD.

 

I run my B+ charge line directly to the passenger side battery with NO fuse involved...my personal opinion is that it is not required however; in a sever front end collision where the CTD is still running after the impact and one or both batteries have been catastrophically crushed due to the impact...a fuse would prevent the alternator from applying full current into a haphazard dead short to ground. Yeah... I saved my alternator from absolute destruction but.... my truck has sustained substantial damage from the collision and six grand worth of body damage....boy, I'm sure glad I saved my alternator 

 

Oh..I'm late in replaying to this...Dan has beat me to it...

 

Cheers

W-T      

[buzzman]

Got it! Thanks a bunch. This is an amazingly helpful forum for those of us who like these 2nd gen CTD trucks.

 

Buzz

[JAG1]

IBMobile is always so helpful. buzzman, if you can please report back about how much your AC ripple drops after this mod. It is an important change from the factories peanut butter and jelly style wiring.

 

 I'm also interested in the other area of the harness that Dripley has reported a couple times that is again fused together with some sort semi soft glue instead of solder. According to Dripley it is in the harness near the ECM. Would be interesting to note what important functions those wires carry. Better to discuss under a new topic so it won't be confused with W-Ts mods.

Edited June 29, 2019 by JAG1

[buzzman]

Well, I finally finished the W-T wiring mod to my 98.5 truck. I had previously replaced all the battery cables and various chassis ground wires. And I replaced the battery clamps with military style clamps. I added the #4awg wire between the negative posts of the batteries as W-T suggested. I ran the new alternator charge wire through a 150amp breaker mounted near the passenger side battery. The ground wire connection, the #8awg and the three smaller wires seemed to be done well. They were crimped and soldered nicely and covered with some heavy duty heat shrink. Maybe I should have left them alone and just ran the #8 wire to the driver side battery...but I did it like W-T did.

 

I checked the AC ripple before and a after the modification.

AC ripple before the mod = .028-.031 vac. This was with all accessories turned off and all noise filters removed. Actually, I tested with and without the noise filters and it didn't make much, if any, difference. During my first measurement I forgot to turn off the blower motor and the reading was .039-.043 vac.

 

AC ripple after the mod = .010-.012 vac. Nice improvement! This was a reading I took after I drove the truck around for about 10 minutes. The first reading I took was right after I got all the wires hooked back up and the reading was higher at .014-.016 vac.

 

I hope this solves my T/C locking/unlocking issue. I want say thanks for all the help I got from this forum.

 

Buzz

 

 

[dripley]

That ground is definitely different from the later models. No solder on them just some the wire smashed together with some funky looking sealer and shrink wrap on them. Happy for your sucess.

[Cummins5.9]

So the factory alternator charge cable runs through the 140 amp fuse in the PDC. The short wire on the other side of the fuse to the battery also supplies power to the PDC right? So nothing is being changed or upgraded here? 

 

Do you think the factory ran it this way simply to have the charge cable fused and they didn’t want the fuse outside of the PDC? 

 

Do you think there is detrimental noise/fluctuations/surging running through the PDC because of the factory design and re-routing the charge cable to the aux battery is safer with regard to the integrity of the PDC?

 

Finally, does anyone have any of the pics from W-T’s post on page 2 of this thread? Presumably these were lost in the server changeover that I read about elsewhere?

 

I believe I’ve read everything available here on the W-T mod (with the exception of any coverage in the high-amp alternator thread, I plan to stay stock for now but good to know it will be prepped for a better alternator in the future). I’m psyching up and getting ready to tear into getting the W-T mod done and the PCM ground improvement done as well. Already fused it. Has anyone done any protective fusing or other measures with regard to the ECM (aside from the ground improvement)?

 

Oh.. also it sounds like a lot of folks are perhaps not doing the additional 2/0 cables from battery to battery. It was mentioned that it was possibly not necessary without going to higher output alternator.. but it seems it would be important when switching charging heirarchy from the primary battery to the auxiliary battery given the temp sensor is beneath the primary battery? Also does this temp sensor go bad in anyone’s experience or is it pretty reliable? Worth replacing proactively? 

 

I had an O3 that I have since sold, but it blew a passenger side battery once for reasons I do not know. I loved that truck except that it was an automatic, otherwise I would’ve kept it. 

 

Thanks to all for all the informative reading.

Brandon

[dripley]

42 minutes ago, Cummins5.9 said:

So the factory alternator charge cable runs through the 140 amp fuse in the PDC. The short wire on the other side of the fuse to the battery also supplies power to the PDC right? So nothing is being changed or upgraded here? 

 

Do you think the factory ran it this way simply to have the charge cable fused and they didn’t want the fuse outside of the PDC? 

 

Do you think there is detrimental noise/fluctuations/surging running through the PDC because of the factory design and re-routing the charge cable to the aux battery is safer with regard to the integrity of the PDC?

 

Finally, does anyone have any of the pics from W-T’s post on page 2 of this thread? Presumably these were lost in the server changeover that I read about elsewhere?

 

I believe I’ve read everything available here on the W-T mod (with the exception of any coverage in the high-amp alternator thread, I plan to stay stock for now but good to know it will be prepped for a better alternator in the future). I’m psyching up and getting ready to tear into getting the W-T mod done and the PCM ground improvement done as well. Already fused it. Has anyone done any protective fusing or other measures with regard to the ECM (aside from the ground improvement)?

 

Oh.. also it sounds like a lot of folks are perhaps not doing the additional 2/0 cables from battery to battery. It was mentioned that it was possibly not necessary without going to higher output alternator.. but it seems it would be important when switching charging heirarchy from the primary battery to the auxiliary battery given the temp sensor is beneath the primary battery? Also does this temp sensor go bad in anyone’s experience or is it pretty reliable? Worth replacing proactively? 

 

I had an O3 that I have since sold, but it blew a passenger side battery once for reasons I do not know. I loved that truck except that it was an automatic, otherwise I would’ve kept it. 

 

Thanks to all for all the informative reading.

Brandon

The pictures are actually on page 1. This is WT's original post. @Mopar1973Man turned it into article that I can never find and it has the pictures also. Just not sure where it is located.

 

With out reading thru it all again the mod was mainly to clean up the length and location of the grounds and clean the crazy splicing in the wiring. Also to get the charge wire out and away from the sensor wires in the loom on the front of block. I dont remeber it being to address anything strange in the PDC. I personally did intstall 1 2/0 + between the batteries when I replaced all my cables with 2/0 about 6 months prior to doing the mod. I also added a #4 - between them after the mod.

 

WT has a rather large electeical load on his truck so the extra cables are of benefit to him but not so for me any way. I know pre mod my batteries would get slightly moist on top on occasions. After the mod they have been dry as a bone. No corrosion on the terminals and I treated them with nothing to prevent it. It was an over site at the time but longer it went without protection and no corrosion the longer I am waiting to see if any corrosion occurs. I have no idea as to why the mod would do this other than pre mod maybe I was over charging a bit. 

[Cummins5.9]

Thanks Dripley.. Yeah I have the 98.5 so I have the “bonus” ground from the alternator to the block just below the Tstat housing. I pulled the loom apart over to the VP and found the splice. As mentioned by another member with a 98.5, mine is shrink wrapped with I believe a metal crimp beneath it. Probably significantly better connection than some of you have discovered on your newer models. 

 

Not sure if this is present on the 99-02 models, but the charge wire drops into a large loom just below the VP and snakes down under the power steering pump, up over the motor mount and around to the inside of the wheel-well.. the lazy in me wants to consider just cutting that cable at the VP area and seeing if I can pull it through to the PDC. Probably not possible given the likelihood that it’s taped throughout. I then thought well, maybe just cut it off at both ends and leave that section in the loom. That looks to be a great deal more work to remove it completely. Not that I’m afraid of work, but time and mobility are becoming factors as well in my projects.. Just wondered if anyone else might have taken the err umm... shorter route on this cable as well.. I guess it’s irrelevant.. I can’t think of any danger in leaving a disconnected section of that cable in the loom.. only if it could become energized somehow which seems pretty unlikely. I’ll tape up the ends just in case. 

 

Edited April 20, 2020 by Cummins5.9

[dripley]

I took the charge wire to the passenger battery and dont remember exactly how it was routed. I then put short cable from the drivers battery to the PDC. Another benefit was reduce ac current off the alternator. Pre mod l was at .035 volts and it dropped post mod to .010 volts.

[OmahaGen2]

On 4/19/2020 at 7:57 PM, dripley said:

I took the charge wire to the passenger battery and dont remember exactly how it was routed. I then put short cable from the drivers battery to the PDC. Another benefit was reduce ac current off the alternator. Pre mod l was at .035 volts and it dropped post mod to .010 volts.

Exactly what I couldn't figure out..What about charge line to the PDC?  And here is the answer, Thank you...not sure how I missed it before or if that was missing, but I was really starting to scratch my head.. Thanks to all that contributed to this..You guys are the best.

[JAG1]

Some doing this Mod are skipping by not adding the 3 additional battery parallel cables that W-T has called for. If you skip this important part you are asking for trouble in the future. You need to do either of 3 options..... 1) complete the battery to battery paralleling cables.....2) move the battery temperature sensor over to the passenger battery..... or 3) use a longer heavier B+ charge wire over to the drivers battery where the temperature sensor already exists from the factory. This very important or you could have a real fire hazard.

 

W-T is very pissed some of you are skipping this important safety feature of this modification on your trucks.

Edited June 14, 2020 by JAG1

[Mopar1973Man]

Not required... just optional. Even my truck without that still 11 to 13mV AC.

[OmahaGen2]

OK, I thought I had this, but I have only to connections that go to my alternator (see pic) and the other end of this alternator lead goes into the large loom & then breaks out by the VP44 and up to the negative side of the PDC.      I also have a power lead going from the drivers side battery to the PDC.

I also have a ground going from the drivers battery to the fender & one from the drivers side to the frame.  (I had already changed out the cables with a kit several months back)

 

Never had a problem except for T/C lock unlock started happening..unhooked the power from the PDC 140 amp to test.......it eliminated the T/C problem.......changed the alternator out, put on a additional ground from the PCM to passenger battery.  Worked for a while...and now I am opened up the loom seperated out the grounds & I am not sure about what to do with the PDC negative. I would think big awg ground, but why isn't my truck fried?   again no other problems or codes..Ok I figured it out.  It looks like a ground cable, but it is NOT..If I had kept reading which I did..I did run a extra ground battery to battery.

And yes I triple checked where it runs to..

Edited June 15, 2020 by OmahaGen2
I figured it out

[JAG1]

3 hours ago, Mopar1973Man said:

Not required... just optional. Even my truck without that still 11 to 13mV AC.

It's required Mike  because if the passenger battery develops a short with age and no battery temperature sensing to limit charging, being the temp sensor is on the other battery you could cook things up real good. So you have those three options I mentioned above that W-T and I talked about.

 

As for me, even though knowing that adding better battery parallel wires is the best option...... I'm still going to run the charge wire to the drivers side battery to get back the temp sensing capability.

 

I'm doing my best here to save you the guys of what I went thru when my alternator got smokin' hot and almost cooked the PCM.

Edited June 14, 2020 by JAG1