Rats nest wiring, setting 12V back to 24V

[DarkSeas]

Hey y'all. Proud new owner of an '86 M1008. Trying to get her running reliably by July. The previous owner converted it to 12V after it caught on fire at the passenger side wiring block. Said he had alternator work done and a 12V starter put in. I want it back to 24V.

I don't know these trucks, but I took a bunch of pictures of what I'm lookin at here. I'd really appreciate some help with this. I've got mechanic buddies and we're all scratching our heads on what needs doing here. These guys know diesels but not 24V. I'm honestly considering pulling all the wires and putting in new harnesses or something, but my buddy Jr told me not to, since it was running when I got it to the house. The 12V starter went out on it, so I got a new starter, 24V. I want to put as much back original as I can.

Attached a bunch of pictures. I've got the positive wires off the batteries, was doing some engine bay cleaning and didnt want to short anything out. Wiring is pretty foreign to me. Appreciate any help you can give me. If youre referencing a picture, please give me the picture # so I can make note of what you're talkin bout. Sorry if craps all out of order and difficult, this is my first post to the forum.

 

[WWRD99]

Hey y'all. Proud new owner of an '86 M1008. Trying to get her running reliably by July. The previous owner converted it to 12V after it caught on fire at the passenger side wiring block. Said he had alternator work done and a 12V starter put in. I want it back to 24V.

I don't know these trucks, but I took a bunch of pictures of what I'm lookin at here. I'd really appreciate some help with this. I've got mechanic buddies and we're all scratching our heads on what needs doing here. These guys know diesels but not 24V. I'm honestly considering pulling all the wires and putting in new harnesses or something, but my buddy Jr told me not to, since it was running when I got it to the house. The 12V starter went out on it, so I got a new starter, 24V. I want to put as much back original as I can.

Attached a bunch of pictures. I've got the positive wires off the batteries, was doing some engine bay cleaning and didnt want to short anything out. Wiring is pretty foreign to me. Appreciate any help you can give me. If youre referencing a picture, please give me the picture # so I can make note of what you're talkin bout. Sorry if craps all out of order and difficult, this is my first post to the forum. View attachment 867129View attachment 867128View attachment 867126View attachment 867120View attachment 867121View attachment 867122View attachment 867123View attachment 867124View attachment 867125View attachment 867126View attachment 867127View attachment 867128View attachment 867129

well...where most people start is at the TMs in the stickies at the beginning of this forum...it has all the info you need to go over all the wiring plus there's one just on the alternators to get them to work right as well...this stuff is pretty straight forward to get going...it doesn't look like the harness has been chopped up...does the glow plug card still work ?

 

[DarkSeas]

well...where most people start is at the TMs in the stickies at the beginning of this forum...it has all the info you need to go over all the wiring plus there's one just on the alternators to get them to work right as well...this stuff is pretty straight forward to get going...it doesn't look like the harness has been chopped up...does the glow plug card still work ?

Yessir glow plugs and everything work fine. I think the harness is original, only thing he added was some aftermarket LED blocks on the front grille guard for better night visibility.

I could get it to crank and start until last weekend, seems like the starter he put in died. Took the batteries out and charged them to full and the starter kept making the same free spinning sound.

I'll have to check out the post you're talking about, this is my first time using forums of any kind, so I'm sorry if it's not proper etiquette. Just didn't know where to even start.

 

[WWRD99]

Yessir glow plugs and everything work fine. I think the harness is original, only thing he added was some aftermarket LED blocks on the front grille guard for better night visibility.

I could get it to crank and start until last weekend, seems like the starter he put in died. Took the batteries out and charged them to full and the starter kept making the same free spinning sound.

I'll have to check out the post you're talking about, this is my first time using forums of any kind, so I'm sorry if it's not proper etiquette. Just didn't know where to even start.

You're in better shape than most if the glow plugs work!! The articles I'm talking about are at the beginning of the forums for the CUCV...it says Tm's n such...they are very long but have every part number and all the info you should need to get it to work right. If you can find someone that has one that helps a ton as well just so you can see how things are run and what goes where...I did notice that there is no diode pack between the bus bars on the firewall...plus it looks like a stereo wire is used for the battery, probably not a big deal on that though. Once you dive into the TM's you can search up part numbers and find original parts or solid replacements. Write it down and make a fun list or keep a couple hundred windows open on the computer so you can find them again.

 

[DarkSeas]

You're in better shape than most if the glow plugs work!! The articles I'm talking about are at the beginning of the forums for the CUCV...it says Tm's n such...they are very long but have every part number and all the info you should need to get it to work right. If you can find someone that has one that helps a ton as well just so you can see how things are run and what goes where...I did notice that there is no diode pack between the bus bars on the firewall...plus it looks like a stereo wire is used for the battery, probably not a big deal on that though. Once you dive into the TM's you can search up part numbers and find original parts or solid replacements. Write it down and make a fun list or keep a couple hundred windows open on the computer so you can find them again.

Yep, I found the list of TMs you're talking about. Guess I just gotta figure out which one talks about engine bay wiring haha. I will probably keep a list, I've already got a running list of things that need doing on her.

Got new injectors and glowplugs, a new 24V starter. As much as I want to wire everything from scratch so it looks nicer, I know my buddy has a point when he said "well it was cranking with the wires as they are, I wouldn't rewire the whole thing, just replace the starter" issue is I got the 24V original starter, and I'm finding out he converted everything 12V. Theoretically I'm guessing it's only like 3-4 wires need rearranging, but which and how are my issue. He said he paid some guy like $130 to convert it to 12V, that really doesn't seem like much so I'm assuming not a lot changed. Here's hoping I can look through the TMs this week and figure out where my rig looks different.

And yes the stereo battery wire bothers the hell out of me lol. And all the connections to the battery terminals, but I figure it can look ugly for the time being as long as I can get it to fire up again.