M38A1 Wiring Harness Build & Info 24 Feb. NEW PIC

1952 - 1968, M38A1, M170, questions, discussions, regarding anything related to the M38a1 series.
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M38A1 Wiring Harness Build & Info 24 Feb. NEW PIC

Post by Duke113P » Tue Jan 25, 2011 3:47 pm

Wiring Harness Information, FOR Everyone to see and know... I post it like this so that everyone knows this information is free for all to use at their own discretion. I have made measurements of the M38A1 wiring harness for the later model M38A1 like mine, a 54' dod M38A1. I have reconstructed so far the front harness for the main lights, marker, horn, blackout and horn swtich. Right now I have a model wiring harness made of this so far. I taking all measurements from whats left of the originals harness and the routing via the Manual as well mainly for the rear. I will be posting photos with a complete set of meaurements for this wiring harness in the coming weeks. I will also post pictures of the working (reproduction) harness I am making myself from NEW military wiring and NOS connectors. Sorry but I am just not able to afford an original harness and I want others out there to know this information if you wish to make your harness as well. I will have complete numbers for the metal connectors (AKA: DOUGLAS Connectors), also I will be posting pictures of how to make your OWN inexpensive DOUGLAS To current M-series wiring adapter. This way if you need a gauge but it has the rubber connectors and a metal housing you can use it with your original or repro-repro made harness until you find the Gold egg to buy the douglas connector gauge, switch, horn etc.


A little background info on the connectors for the wiring harness build....(For those interested, if your not, stop reading... or go to the next paragraph)

Each Wire to wire Douglas connection has NINE! Pieces for that one connection total BUT you only need 2 sets of four pieces! They are as follows...

Image




Yeah.. I know... The only good part, is only one connector is required per WIRE to WIRE connection.

And then here is the double connector to single or vice versa...
Image

These pictures are from a great article on the Douglas system wiring at http://www.willysmjeeps.com

Then you will need of course the special Douglas connector crimper!! OMG!! These things can get expensive! They have em on EggBay from time to time. But be prepared to pay top dollar for them. I am currently borrowing a crimper from another G503 member. Anyways, as I build it, I will post measurements and information. I already have all the components I need as of posting this. You can find these connectors for sale via Vintage wiring of Maine and Midwest Military Vehicles.

*** FACT::::::: A temporary solution to make a douglas connector gauge work with an M Series-Post Douglas connector is to make a temporary converter cable from old harness parts of pieces from old Marker or Tailights. I have gone through six pairs of taillights to only end up with good useable hulls but the innerds were shot! The connectors were salvageable, I simply made a convert from these left over wires. I have even gone so far as to make a few temporary wire connection on the M38A1 that appear to be stock douglas connector connections but in fact are only the metal shells, I used BUTT connectors and crimped it in place, some electrical tape ___EVEN some shrink tubing over that for good measure...___and presto! It looks authentic outside with the shields in place. Just remember these types of fixes are only temporary till you make the correct repairs, if you want it to be military stock that is. IF you plan on just running it around and enjoying it for now... like I do... then go ahead.. indulge yourself and enjoy the ride! Just do not try to ford water crossings or put the diver suit on and snorkel kit then go for a drive... just my own little disclaimer on that.

NOW... to completely throw you off center... you can make your wiring harness using the newer style M series Rubber Connectors... I am sure someone by this time is just burning in the head to post the correct term for the newer style of rubber connectors.... I will keep this updated as I make headway into it.

REMEMBER FOLKS: ALWAYS disconnect your battery before working on anything electrical on your M38A1, always close your tool box after you have retrieved your tool of choice... as your "friends" are waiting to make up their shortages, when in Europe be sure to have your back to the public when attending to mother natures call, the Autobahn does have a speed limit...in certain parts, look failure square in the eye AND kick him where it counts...
Never quit... Never Accept Defeat...

Last but not...the last comment....

I DO NOT CARE, who makes a good or poor reproduction so please do not post that here, start your own post about it. We are men! We have been able to do great and terrible things... but lets get this going and make our own wiring harness. It will be just as good, AND yes.. it will have the correct wiring connections marked as per the reproductions... since DING DING...the connector Numbers for the M series when it comes to the basics are the same... oh and if you want to see the variations of the little aluminum number / id tags for the wire I will post them five different vairations that I have encountered from NOS parts and take out. <----I had to cover that as well.
Last edited by Duke113P on Thu Feb 24, 2011 6:34 am, edited 4 times in total.
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Re: Wiring Harness Information, FOR Everyone to see and know...

Post by DJ » Tue Jan 25, 2011 7:23 pm

"newer style M series Rubber Connectors" = Packard :lol:

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Re: Wiring Harness Information, FOR Everyone to see and know...

Post by Duke113P » Wed Jan 26, 2011 5:18 pm

Here it is the begining of the wiring harness in its collected bags separated waiting to be installed. I figured it was fitting to see what I have to start with. YES, some of the shells are take outs, the shells are still good, they work, they may not be pretty, but my M38A1 is a working jeep not a trailer queen. I will clean the rust and corrosion out of them and hit em with a light coat of clear coat for endurance. The one bag with the long pieces of wire and coonnected shells are a complete take out M38A1 headlight harness fresh from the local junk yard. The rest of the poor jeep had been scrapped except for the grille and some frame pieces I think. You will see also the Douglas military crimp tool under the wire cutters. I will have new pictures as I progress on this project.

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Re: M38A1 Wiring Harness Information, 26 Jan NEW Pic

Post by Duke113P » Thu Jan 27, 2011 2:21 pm

Here are some closeups of the terminal in the crimper and an old terminal compared with a NOS one.

Image



Image

Interesting note in the bottom photo, look at the double crimp on this connector. The crimp at the wire end is a different crimper style. A six point crimp tool was used for this. I lightly crimped my contacts with the four point crimper. The wiring harness example is from 10-54. Also, it is a good idea to service your crimping tool before you use it. clean it, relube it and it makes the crimping process easier.
Last edited by Duke113P on Thu Feb 24, 2011 5:29 am, edited 1 time in total.
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Re: M38A1 Wiring Harness Information, 26 Jan NEW Pic

Post by SB5477 » Thu Jan 27, 2011 11:24 pm

The electrical/technical part all clear in your comment, I have only one question.
when in Europe be sure to have your back to the public when attending to mother natures call,
At home you do it facing the public? :D

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Re: M38A1 Wiring Harness Information, 26 Jan NEW Pic

Post by Duke113P » Sat Jan 29, 2011 4:51 am

Here in the states, you can be arrested for relieving yourself in public even with your back turned. Hogyan? I was there in your neck of the woods in 1995 at Kaposjulak Airfield for a few weeks before we went into Bosnia. <--corrected spelling.
Last edited by Duke113P on Sat Jan 29, 2011 4:11 pm, edited 1 time in total.
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Re: M38A1 Wiring Harness Information, 26 Jan NEW Pic

Post by SB5477 » Sat Jan 29, 2011 5:18 am

You can get arrested in the US for many things not taken so seriously in other countries, but you should use the washrooms in all places you visit. While you probably will not get arrested here for this, the police will not give you a reward either. What is the meaning of " yoru neck opf "?

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Re: M38A1 Wiring Harness Information, 26 Jan NEW Pic

Post by Cuz » Sat Jan 29, 2011 8:20 am

yoru neck opf the woods
Correct spelling is: "your neck of the woods"

US colloquial expression meaning "in your neighborhood" or "near where you live" :wink:
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Re: M38A1 Wiring Harness Information, 26 Jan NEW Pic

Post by Duke113P » Sat Jan 29, 2011 4:15 pm

I corrected the spelling. SB.. of course you can get arrested for doing anything that a police or law enforcement officer does not like you doing or they consider offensive. Germany 1996, you could pee out in public, on the Volksmarchs, there were no bathrooms out there, even at the Bier stands, but you can take a couple of steps into the woods, back to everyone walking by and relieve yourself, without anyone being offended or fear of being arrested. its mother nature, she calls you gotta go.

Now back to the wiring harness....
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Re: M38A1 Wiring Harness Information, 26 Jan NEW Pic

Post by Duke113P » Sat Feb 05, 2011 3:47 am

Front Wiring Harness aka grille harness is almost complete. This is by far the easiest piece to do first, all wires are easy to get to and measure. Now understand that the below listed measurements ARE appoximates. I will tailor these down to fit the jeep once I install it. The good thing about the headlight wires, if I am a tad too long thats ok, I can store the excess in the headlight buckets.

NOTE: Lessons learned so far...
1. Before soldering and crimping in place your terminal, be sure to have preinstalled the Shell and Bushing. Remember TWO Crimps, just like in the above comparison picture. I drop a little solder in the terminal, heat it up, install the wire, let it cool, then crimp and crimp.

2. Lightly lubricate the rubber grommet before you try to slide the grommet on to the terminal. Makes life a whole mess easier and saves your finger tips.

3. When making the connection for the two to ones (there are three on the grille harness for the lights) NOTE: that the two terminals leading from the lights to the single main connection are terminals at the base for the purpose of waterproofing. I did not have the larger head terminal so I use the 14 gauge ones I had on hand. I used two grommets inside the two to one grommet to help keep the water out. Again lightly lube these makes life alot easier.

4. From measuring to making I have about five hours invested in the front grille harness. How much money? My COST....ZERO $'s

5. You can reuse the number tags off old wiring harness for your newly made one.


I WILL have the measurements up today once I have the final fitting completed, as of this update I have completed final fitting and taping. I will have pictures and mseaurements today.
Image

Sorry about the fuzziness of the pic, I had to use my cell phone. The special battery that our Digi camera uses died a few days ago.
So there it is... not so hard once you get the measurements.. NOW

NOW... I know it may not look like the correct length, but I made it plus and minus a few inches to help out with installation, mounting and repair of parts. I made new wires for the blackout marker lights... AND.. I know someone is asking where are the ground cables? I reused the original ground end and made new ones already / installed them before I took the picture. Total time including wrapping is about 5 1/2 hours. Not bad I think, It tests fine with the multimeter we I will do a test install for function later today since the weather is good.


... Some will note that the three 2 to 1 connectors are not the same length, I offset one to make the flow easier. Original wiring harnesses have all three clumped together. My little offset makes working with these NOS shells easier to connect with the additional room for your fingers.
Last edited by Duke113P on Sun Feb 06, 2011 5:38 am, edited 1 time in total.
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Re: M38A1 Wiring Harness Build & Info 5 Feb. NEW Pic

Post by Old Dodge Guy » Sat Feb 05, 2011 4:14 pm

Excellent info so far. I just thought I would add my 2 cents, or so.
While I have the jeep torn down, I am installing a new wiring harness, and wiring it for turn signals. Since I am using a NOS wiring harness, without turn signals, How do I go about that? Well, to make it simple, I just used a flat ribbon cable from a trailer wiring kit. The flat white, brown, yellow green 4 wire cable. I just ran the new flat along the old wiring harness and taped over the lot from end to end. To make the colors "go away" and look military, I ran black heat shrink over the colored wires before crimping on the military ends and douglas connectors. The heat shrink was run under the tape before finishing the tape job, so that end was covered. Nearly impossible to tell the difference. If I can figure how to send pictures, I'll try to post a few here.
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Re: M38A1 Wiring Harness Build & Info 5 Feb. NEW Pic

Post by Duke113P » Sun Feb 06, 2011 5:35 am

I went ahead and installed the grille wiring harness yesterday evening. IT WORKS! :shock:

NOTE: As I attached every terminal to the wires I immediately tested the wire to ensure proper operation. This prevents any problems before final assembly and once I wrapped the wires, I tested them one more time. Overkill? Yes, BUT it is better to be correct beyond a reasonable doubt than to go back and undo your work fix the problem and rewrap the wiring.

Before I installed the wiring harness for the headlights, blackout markers, I made sure to mark the old wiring harness that was still in place. I removed and installed one complete wire at a time, helping to keep confusion and mistakes to zero.. almost. I did get the left blackout marker confused with a left headlight terminal. Thank goodness I had the wires all marked with old wiring harness numbers. I reused the little aluminum numbered id tags from old wiring harnesses that I have come across over the past few months in preparation for this build.

Once the wiring harness was installed, I tested to see what I had with the wires at the three 2 to 1 terminals. This is where the wiring harness gocombines from the six wires to three. Two of these wires go to your dimmer switch, the other wire for the blackout marker lights is connected directly to your light switch (Military three levered Switch/ control box, not a civilian pull style switch). The following is a list of numbers and their correcsponding wires that I used for the front grille harness....

Remember that these numbers are the same for almost all M series light systems. Some other M series vehicles will have more wire numbers than this for sure since this system does not have the turn signal system involved.

Wire numbers Used for the front / griller wiring harness.

17 Headlight dimmer switch 2 to 1 connector: I installed one wire from the grille harness back into the connector, there are two
there, I have a temporary wire in place for the light switch. I will cover the rest of that piece when we get to it.

18 Headlight dimmer switch all the way to the headlights.

20 Blackout marker lights from the marker lights all the way to the light switch.

91 Ground wires at headlight buckets

I guess its time to show the actual wiring diagram.... almost forgot about that part... thanks to my wife for pointing this out.

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Re: M38A1 Wiring Harness Build & Info 24 Feb. NEW PIC

Post by Duke113P » Thu Feb 24, 2011 5:23 am

Here is the main harness laid out in the floor of the kitchen. My wife was very understanding.. she and the kids were fast asleep when I did this part. You need 169 inchesof wire times four for the four rear tail light wires runnig to the rear. Thats not counting the split offs which are easy. Its the 169" length that has brought me to a stop for now on the rear main, I have two lengths that long with two splits each. I need two more, so it is off to the scrap yard once again to harness some M35's wiring harnesses before they are scrapped.
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Re: M38A1 Wiring Harness Build & Info 24 Feb. NEW PIC

Post by FrankenJeep » Thu Feb 24, 2011 8:06 am

What is the difference in the M38 and A1 harness? I need to redo mine!

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Re: M38A1 Wiring Harness Build & Info 24 Feb. NEW PIC

Post by FrankenJeep » Sat Feb 26, 2011 5:25 am

Anyone?


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