I am currently getting ready to 3g swap my 84 6.9 idi but running into something’s that I haven’t found any answers to in my searches. There is plenty of great write up’s on this process but can’t seem to find what I need. My first question which may be a dumb one is, about the two wires I have circled (dark green & orange wire) The green wire has a 14 gauge fusible link and the orange wire has a 16 gauge fusible link and where it becomes confusing is that turns into a single yellow wire that hooks up to the battery cable on the old alternator harness, my question is when deleting the old harness what happens with the orange and green wires/yellow wire?

 

Anyone here with an EVTM for an '83-'91 IDI truck? They all have the same 1G alt so any of them will help this guy out on this. I did this so long ago I forgot where the wires go and what they are, and my own EVTM is with the truck an ocean away currently.

 

Those fusible links look like they go to the glowplugs. I did the 3g swap a couple months ago on my 87, and I don't have half the wiring you have. You're going to eliminate the voltage reg so you'll lose a few there.

 

Here’s a closer photo of the orange wire and green wire.

and thanks for any help guys, if there’s any more photos I could take to make this a little bit more clear just let me know.

 

here is an updated photo of what everything looks like with the regulator out. All wires wrapped in blue masking tape went to the old alternator wiring harness including the thick yellow one, basically trying to figure out what wires I’m going to lose and what wires I will be using for the 3G swap
In the picture below you can’t see which wires are wrapped in masking tape but it’s the red, black and both yellow wires that were spliced into the old alternator wiring harness.

I should mention that the truck has trailer hook ups.

 

Ok so the light green wire with red stripe that you have labeled as "stator" is actually the key-on trigger signal for the voltage regulator, extend that till it meets the same colors wire coming out of the 3G plug. By the way it is incorrectly positioned in your old VR, should have been on terminal "I" not "S".

The wire with the ring terminal and fuse link, ditch that, is your old charging wire and obviously we'll undersized for the job now. Replace it with a 2-ga cable from your favorite parts store, however cut the shifty steel ends off it and give it proper copper ends in suitable size, I've found that 4-ga ends fit quite beautifully on 2-ga cable. The hole for the alternator-side will be 1/4", other end should be 3/8". Use a Megafuse inline, most common size is 175 amps and that will be sufficient to protect the truck should the alternator short to ground.

Orange wire from the old VR harness (the one that has no fuse link KS on it) is field coil for the old 1G, you no longer need this as the 3G does this internally.

Yellow wire that was cut, the one that near the old VR has two red wires spliced into it - verify that you have exact battery voltage on its end that is now dangling loose on the truck side of things, and if you do extend it to meet yellow wire on the 3G plug - this is your battery voltage sensing wire, it tells the VR how much power it needs to squeeze out of the alt.

 

Does your truck have a voltmeter or amp-meter gauge on the dash? After these two wires spliced together into one yellow wire, where does that yellow wire go?

 

It has one of these:

The yellow wire was originally spliced into the original alternator wiring harness. Pictures below👇🏼



You’ll see in this photo I circled where the yellow wire spliced into on the original alternator wiring harness.

in this last photo you will see a black wire with orange tracer feeding the orange wire and a yellow wire feeding the dark green wire, I believe the black wire with orange tracer is feeding the headlight switch inside the cab but haven’t figured out where the yellow one goes and what it’s for.





thank you for your help, When I hook it up to the starter relay or battery positive post do you think there is a need to change out those fusible links? I bought this 225 amp Alternator from CDD👇🏼






Thanks for all the help! When installing the yellow wire to either the starter relay or positive terminal on battery do you recommend replacing those fusible links? I bought this 225 amp alternator from CDD👇🏼

 

This is what the truck has:

In the next two photos you’ll see that the yellow wire originally went to the old alternator wiring harness:


In this photo I circled where the yellow wire splices into the original harness.

in this last photo you’ll see a black wire With orange tracer feeding the orange wire and a yellow wire feeding the dark green wire, I traced back the black wire with orange tracer and I believe it’s feeding the headlights switch in the cab but not sure where the yellow wire goes.

thanks again for the help!

 

Right so that fat yellow wire on factory form bled current current off the alternator's charge wire then split it along the green and orange wires and send it down thru the fuse links to wherever. So add a ring terminal to said yellow wire and hook it up either to the starter relay (the stud where most wires are connected to) or extend it to reach the battery's positive terminal.

Your gauge is an amp-meter indeed, don't one what to do with one tbh, all my 3G conversations have been on voltmetered vehicles.

 

Thanks for all the help! When installing the yellow wire to the starter relay or positive battery cable would you recommend replacing the fusible links? I purchased this 225 amp alternator from CDD👇🏼

 

Thanks for all the help! When installing the yellow wire to The starter relay or the positive battery post would you recommend replacing the fusible links? I’ll be installing this 225 amp alternator.

 

Sorry for the multiples of the same post my computer was on the fritz.

 

No worries man 👍

Right so your asking about the red and green fusible links right? Then no, I wouldn't mess with them, they're a sealed thing that could be good for all eternity - if you to replacing them you're making splices where corrosion can start, not worth it unless the links are burned out which you'd know right away.

 

Ok thanks for that info!

Big yellow wire: put ring connector on end and connect to starter relay/positive battery post.

Green wire: Connect to green wire on alternator.

Yellow wire: find exact battery voltage.

in the picture below what exactly do I do with the black wire and red wire, (The black wire was connected to old alternator wiring harness) (The red wire was also connected to old wiring harness)