m38 light switch

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
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roughneck20
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m38 light switch

Post by roughneck20 » Sun Jul 28, 2019 3:01 pm

so i own a 1950 cj3a and its 6v original wires and i plan to convert it to an m38 but i just recently as in today set the (i believe ammeter wire) on fire and the wire separated in 2 because of the wrapping of the wire is no good and i think it was up against the starter push rod which caused all this and well anyways i was eventually going to buy a new 12v harness and convert but i noticed the light switch of an m38 has a big screw plug and i cant find that plug anywhere or see anything like it in the harnesses so im just wondering if i can use the switches or if there is an adapter etc
1952 M38


mdainsd
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Re: m38 light switch

Post by mdainsd » Mon Jul 29, 2019 9:16 am

You are in for a task. There are a couple of approaches. The most expensive is replacing all the light fixtures, generator, starter, distributor, regulator gauges, light switch AND the whole harness.

How far do you want to go with your conversion to M38? You could go as simple as tail lights, headlights and dash board updated to look like a M38, running 12V components under the hood)

Tell us your goal and we can help. There is so much to do to do it completely, probably cheaper to buy a M38? One of my M38s is a combo of 24V and 12V. everything but the gauges running on 12V (for reliability and availability of parts). The gauges run on a 12V to 24V convertor. If you don't open the hood, there is no way looking at the Jeep to know that the electrical system is this way.

That big connector is readily available if you go that way. Look on the big online auction site for "military wiring harness" often there are new ones being sold that the owner doesn't know what they fit. Suitable for salvaging.
52 M38 2X, '52 M37, '44 WC51, '42 WC 56/57, '50 CJ-V35(U), '42 GPW, '44 M3A1 Scout Car, 2010 M-Gator

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Re: m38 light switch

Post by Joe Gopan » Mon Jul 29, 2019 10:41 am

OEM M-38 Wiring from 50-52 era has poor rubber ibsulation to start with as many others from same time period,( M-37, M-38, M-135,) etc. By the time it was 7-8 years old it turned crumbly. Do not try to reuse it as there will be probs with bare wire.
Rule one on M-Series 24 Volt MV's is always disconnect the batteries before attempting work on electrical parts, especially the dash. I can't begin to tell you what usually happens when an unsuspecting GI attempts to pull the Instrument panel plate away from the dash on a 24Volt truck.
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roughneck20
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Re: m38 light switch

Post by roughneck20 » Mon Jul 29, 2019 12:36 pm

mdainsd wrote:
Mon Jul 29, 2019 9:16 am
You are in for a task. There are a couple of approaches. The most expensive is replacing all the light fixtures, generator, starter, distributor, regulator gauges, light switch AND the whole harness.

How far do you want to go with your conversion to M38? You could go as simple as tail lights, headlights and dash board updated to look like a M38, running 12V components under the hood)

Tell us your goal and we can help. There is so much to do to do it completely, probably cheaper to buy a M38? One of my M38s is a combo of 24V and 12V. everything but the gauges running on 12V (for reliability and availability of parts). The gauges run on a 12V to 24V convertor. If you don't open the hood, there is no way looking at the Jeep to know that the electrical system is this way.

That big connector is readily available if you go that way. Look on the big online auction site for "military wiring harness" often there are new ones being sold that the owner doesn't know what they fit. Suitable for salvaging.
well seeing as my 3a tub is beyond fixing there is a guy in my state that has an m38 tub and i plan on buying it and welding a floor into it and then using it on my 3a and start my conversion to an m38 i only plan to do as much as i need to to make it look as real as possible outside and the inside will remain mostly the same unless it needs to be changed etc
1952 M38

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Re: m38 light switch

Post by devilnutz » Mon Jul 29, 2019 4:24 pm

Call Vintage Wiring of Maine. They took the time to talk me through what changes to original would be needed to fit my jeep, then built a new harness.

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Re: m38 light switch

Post by mdainsd » Mon Jul 29, 2019 4:43 pm

Well an M38 body will help a bunch! You get the instrument panel cutout, the cowl battery box, the correct small glove box and the cutout for the light switch. If you replace the floor be sure to get an M38 floor, there is a much bigger transmission opening in them as opposed to CJs. Hopefully you get the grill and hood as they are unique to the M38 and noticeable from a mile away. Fenders don't matter, just add holes to the drivers for the BOD light.
52 M38 2X, '52 M37, '44 WC51, '42 WC 56/57, '50 CJ-V35(U), '42 GPW, '44 M3A1 Scout Car, 2010 M-Gator

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Re: m38 light switch

Post by roughneck20 » Tue Jul 30, 2019 2:40 am

mdainsd wrote:
Mon Jul 29, 2019 4:43 pm
Well an M38 body will help a bunch! You get the instrument panel cutout, the cowl battery box, the correct small glove box and the cutout for the light switch. If you replace the floor be sure to get an M38 floor, there is a much bigger transmission opening in them as opposed to CJs. Hopefully you get the grill and hood as they are unique to the M38 and noticeable from a mile away. Fenders don't matter, just add holes to the drivers for the BOD light.
ya the guy with the body has a hood and windshield and tailgate to go with it so im just gonna but it all and use my fenders which need some love/repair and ill buy an m38 grill at some point and yes an m38 floor is definitely what ill get
devilnutz wrote:
Mon Jul 29, 2019 4:24 pm
Call Vintage Wiring of Maine. They took the time to talk me through what changes to original would be needed to fit my jeep, then built a new harness.
are they expensive and ill look into them
1952 M38

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Re: m38 light switch

Post by devilnutz » Tue Jul 30, 2019 7:29 am

I spent around 900 for complete wiring including all the little pieces for Douglas connectors. This was for new manufacture to original spec, except for my changes. They do sell individual sections of the harness but do not remember the price. As stated above, if you are looking to save a few bills and know your way around wiring you can find harnesses and adapt to your need. Im not so confident in my wire ability and Vintage is plug and play, so to speak.

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Re: m38 light switch

Post by roughneck20 » Wed Aug 07, 2019 6:23 am

does anyone know or have any wiring diagrams for the wires coming out of the plug and where/what they connect to so when i go to try and wire it i sorta have an idea whether it will work or not cause ive seen the code numbers in some diagrams but there for humvees and not a jeep and dont know where to wire them up
1952 M38

mdainsd
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Re: m38 light switch

Post by mdainsd » Wed Aug 07, 2019 8:17 am

That diagram is around, I saw it in another thread here just recently.

The good thing about Military wiring diagrams and harnesses is that the wire number means the same thing regardless of vehicle i.e. #22 brake light circuit. The lights on a hmmwv are the same function and name as those used on a M38.
52 M38 2X, '52 M37, '44 WC51, '42 WC 56/57, '50 CJ-V35(U), '42 GPW, '44 M3A1 Scout Car, 2010 M-Gator

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Re: m38 light switch

Post by mdainsd » Wed Aug 07, 2019 8:21 am

This thread:

viewtopic.php?f=105&t=303276

scroll down and there is the diagram for the switch
52 M38 2X, '52 M37, '44 WC51, '42 WC 56/57, '50 CJ-V35(U), '42 GPW, '44 M3A1 Scout Car, 2010 M-Gator

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Re: m38 light switch

Post by Joe Gopan » Wed Aug 07, 2019 11:28 am

The TM for your M-38 has the wiring circuits listed..
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO


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