Posted: Fri Feb 04, 2022 7:00 pm Post subject: Crusty Old Wires - What can I do with an M35 Front Harness?
Hi all!
I'm new the forum, so thank you for having me. I've found the information on here extremely helpful.
I'm the proud owner of a new-to-me 1953 M38A1. I have a no spark issue that is the current project on deck. In the process of removing, cleaning, and replacing distributor parts, I have noticed an issue with my #12 wire (Ignition Switch to Coil), which has caused me some regression back into the wiring of this unit.
I have noticed some anomalies that were contributed by prior owners as follows:
1.) The ratty coil wire (#12) is coming directly from the regulator harness and apparently connects back to a civvy ignition switch in the dash. I would like to replace this wire, but I don't feel like there's any way to connect this thing. All of the wires are just deteriorating and there's no douglas connector anywhere.
2.) The original ignition switch, that I believe would have had four douglas connectors, has been replaced by a two post (screw nut style) switch that connects the large positive battery lead to the starter.
The body of this unit is not really a candidate for restoration, so I'm not wanting to pour a lot of money into it. I just want something to tinker with and possible tool around deer camp in. As such, I am looking for economical alternatives.
I feel like this will provide me with a start, but I think I will need to also replace my ignition switch with something that connects to 4 douglas or packard connecters. I have plans to remove the civvy ignition switch altogether and try to clean up the rats nest of wiring.
Also, does anyone know of a source for mil spec wire by the foot that will fit the douglas and/or packard connectors?
I know this post is a bit of a ramble, but I'm trying to get some thoughts out there for hopefully someone else to chew on and enlighten me with their knowledge. Thanks so much!
Joined: Oct 02, 2014 Posts: 2004 Location: South Carolina, Dorchester County
Posted: Fri Feb 04, 2022 8:38 pm Post subject:
Welcome David!
It sounds as if you're maybe not interested in keeping it original military configuration, or are you? Douglas connectors and Prestolite wire are pretty much military stuff and generally more expensive. You can buy 100 or 50 feet bundle of fresh military Prestolite 14-gauge wire on fleabay for about 50-cents a foot.
If you want real economy around the deer camp (maybe not even registered for road use?) you could get by very cheaply by buying a spool of automotive wire and a bag of crimp terminals instead of any kind of pre-built harness for $100+ and Douglas connectors.
This assumes that with a wiring diagram and some basic electrical skill you know what to do? Douglas connectors are $5 a pop (both sides) instead of pennies for a plain crimp terminal.
Is the truck still 24 volt? Does it matter if it is? You'll find 12 volt parts much much cheaper and easier to find. If it's 24 volt and you want to keep it 24 volt, hang on to your wallet because it's going to get expensive pretty fast.
With answers to the above questions you'll probably get more better suggestions.
Good luck! _________________ Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51
“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari
Yes it is always important to provide your readers with a good picture of the lay of the land on your project questions. Is it still a 24V jeep? Or is it a 12V jeep now? How much of the jeeps original stock form equipment and wiring still exists. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Thanks, guys. This unit is still 24V, clean title road registered. I'd love to take it to work a couple of days a year, but that may be a long way off. For now, though, around the block or out of the garage would be great.
Your questions, Ron and Wes, hit to the nexus of my current struggle with this. I'm a purist. I like OEM parts in my daily drivers. I hate frivolous upgrades. I like to have things the way that they were meant to be.
I think on this, though, I have to break with my current dogma and come to a new, perhaps temporary, way of thinking. I have one, almost two kids in college, and I can't spend $700+ on period correct wiring harnesses and OEM switches/ harnesses. Anything that I can do, now, to get this jeep functional, can be undone later when I have more disposable cash, to make it more period correct.
More on the jeep... I see many rusted out Douglas connectors behind and under the dash. Many have been cut/terminated, and wrappped, perhaps in a conservation effort from a previous owner. I think I'm dealing with an original wiring harness from the regulator, but it has been modified to pull out the wire for the distributor, somehow.
I'm not afraid of crimping my own and making connections, but I don't know about the actual new wire. I have read forum posts about the thickness being different. I feel like I can find everything on online, except for the specific wire.
1.) The ratty coil wire (#12) is coming directly from the regulator harness and apparently connects back to a civvy ignition switch in the dash. I would like to replace this wire, but I don't feel like there's any way to connect this thing. All of the wires are just deteriorating and there's no douglas connector anywhere.
The #12 wire should run from the "ON" side of the ignition switch to the distributor. Wire's 10 & 11 supply the +24V to the ignition switch.
2.) The original ignition switch, that I believe would have had four douglas connectors, has been replaced by a two post (screw nut style) switch that connects the large positive battery lead to the starter.
The large thick battery plus cable runs direct from the inboard battery to the large terminal on the starter itself. This fat wire should not be routed thru the ignition switch at all.
The early M38A1 operator's handbook, TM 9-804A, wiring diagram.
The newer M38A1 operator's handbook, TM 9-8012, wiring diagram
It is quite clear you have some very inventive wiring which usually also points to various substituted components. This is why you will need to provide us a detailed list of your electrical components listing their make/model/PN along with good quality photos of them.
Are you using the free to download parts manuals and technical manuals for your M38A1 found on our web site's downloads page? Consulting these manuals is the first step to proper troubleshooting. For example you cannot identify proper wiring components or their gage and wire type yet most wire sizes are given in the FREE download PDF parts manual.
Joined: Oct 02, 2014 Posts: 2004 Location: South Carolina, Dorchester County
Posted: Sat Feb 05, 2022 11:55 am Post subject:
David,
Is the 24V generator and regulator charging system working correctly for your twin batteries?
Are all the gauges working?
Do all the lights and horn work?
A complete assessment of the entire electrical system could help decide how best (and economically) to proceed.
For example, if everything works and only wires need to be repaired or replaced, that could be done fairly inexpensively by salvaging used Douglas connectors or using Packard connectors and would be cheaper than if you have to replace 24V components and also the wiring.
Submerge the Douglas shells in white vinegar for a week and then a little light wire brushing should bring them back to life. You can buy new pins to crimp on the wire for them cheaper than if you had to buy all the pieces.
Can you post some photos?
Where are you? _________________ Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51
“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari
1.) The ratty coil wire (#12) is coming directly from the regulator harness and apparently connects back to a civvy ignition switch in the dash. I would like to replace this wire, but I don't feel like there's any way to connect this thing. All of the wires are just deteriorating and there's no douglas connector anywhere.
The #12 wire should run from the "ON" side of the ignition switch to the distributor. Wire's 10 & 11 supply the +24V to the ignition switch.
2.) The original ignition switch, that I believe would have had four douglas connectors, has been replaced by a two post (screw nut style) switch that connects the large positive battery lead to the starter.
The large thick battery plus cable runs direct from the inboard battery to the large terminal on the starter itself. This fat wire should not be routed thru the ignition switch at all.
Ok, thank you. That confirms what I was reading on the wiring diagram.
Thank you for the redirection on the early and late M38A1 wiring diagrams. I was erroneously using the colored M38 that I found on the site.
Quote:
This is why you will need to provide us a detailed list of your electrical components listing their make/model/PN along with good quality photos of them.
Distributor is an Auto-Lite AU4006UT
Regulator is an Auto-Lite VBC-4002UT
Starter is an Auto-Lite MCZ-4001UT
Generator is a Prestolite GHA-4804CUT
--- More to come on the pictures ---
Quote:
Are you using the free to download parts manuals and technical manuals for your M38A1 found on our web site's downloads page? Consulting these manuals is the first step to proper troubleshooting. For example you cannot identify proper wiring components or their gage and wire type yet most wire sizes are given in the FREE download PDF parts manual.
Yes, thank you. I have been downloading and studying them intently. I am struggling with the parts list ORD 9 SNL g-758. I can't make out some of the pictures of the wiring and how they relate back to the listed components of the wiring.
Thanks for the other links and the suggestions about the photo albums. I will check those out, next.
Quote:
Is the 24V generator and regulator charging system working correctly for your twin batteries?
I'm not sure. The unit is not currently running. It was running poorly when I purchased it and it has since lost spark. I assumed that I had left the ignition switch on and fried the coil. So, I replaced the coil to no avail. Since then, I have replaced every component in the distributor and the spark plug wires.
Quote:
Do all the lights and horn work?
No. No horn and only the headlights work, which I believe I can attribute to a previous owner's excessive use of red wiring.
I have pictures, but I'm still figuring out how to post them.
Quote:
Can you post some photos?
I took some today to share, but I'm still figuring this out. Do most members find external hosting for their photos that they share or do they request photo galleries to accomplish this?
Quote:
Where are you?
North Little Rock, AR
I'm going to get this photo thing figured out, tonight, and share some pictures of what's going on here.
Joined: Oct 02, 2014 Posts: 2004 Location: South Carolina, Dorchester County
Posted: Sat Feb 05, 2022 3:14 pm Post subject:
Hi David,
In case it helps, here's 3 links to the same vendor (Federal Military Parts) who sells fresh mil-spec Prestolite military wire from his home site and also on the 2 other common sources. Not all the same pricing.
These are all 14 gauge wire, which I believe is the majority of wire on your truck. You might need a few feet of 12 gauge, but everybody seems to be out of stock with that gauge in Prestolite. A quality automotive wire would easily do instead.
Other than the heavy gauge battery and starter cables, those are the only 2 sizes of wire on the truck that I'm aware of (12- and 14-gauge).
I host my photos on this site in an album that Wes can set you up with. I find it easier than dealing with (yet another) 3rd party host.
Good luck! _________________ Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51
“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari
Last edited by RonD2 on Sat Feb 05, 2022 3:18 pm; edited 2 times in total
The harness you linked to is a Packard style. Not much help there other than the wire. _________________ '52 Dodge M37, '42 GPW, '48 FrankenJeep CJ2A/M38, '50 CJV-35(U), '51 M38, '42 WC-57 Command Car, '44 WC-51 Weapons , (2) M1941 Sperry 60" Anti-Aircraft Searchlights, John Deere M-gator, '44 White M3A1 Scout Car
Now make a new post of your own requesting a photo album. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
In case it helps, here's 3 links to the same vendor (Federal Military Parts) who sells fresh mil-spec Prestolite military wire from his home site and also on the 2 other common sources. Not all the same pricing.
These are all 14 gauge wire, which I believe is the majority of wire on your truck. You might need a few feet of 12 gauge, but everybody seems to be out of stock with that gauge in Prestolite. A quality automotive wire would easily do instead.
Other than the heavy gauge battery and starter cables, those are the only 2 sizes of wire on the truck that I'm aware of (12- and 14-gauge).
RonD2, you're the man! This is exactly what I needed. Thank you.
Also, wesk, I appreciate the direction and approval of the photo gallery. Now, I can show you what I'm working with here. I think I'm just going to take it slowly and replace the non-working after-market modifications with parts that would have been the way they should have been.
Here is a picture of my ignition wire incorrectly coming from the wiring harness:
Here is the aftermarket two post ignition switch:
Here is under the dash, where the light switch has been bypassed to create a new light switch and an add-on keyed ignition switch has been added. Lots of red wire here:
And here is a step back from this glorious project:
Joined: Oct 02, 2014 Posts: 2004 Location: South Carolina, Dorchester County
Posted: Sun Feb 06, 2022 1:57 pm Post subject:
Glad to help David.
The same vendor selling the wire has new mil-spec ignition switches that are correct for the M38A1 (Packard connectors) for $70, but you can find the same one here for $45 https://eriksmilitarysurplus.com/igswformvems.html
I assume you'll let us know how it's going after you do some wiring clean-up?
Good luck! _________________ Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51
“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari
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