M38 wiring harness

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
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M38 wiring harness

Post by jamsstuff » Sat May 31, 2008 8:46 am

:? Hi:
Need some advice. A little background. I bought a 1948 CJ2A on ebay. I found the chassis, engine, drive train to be in good working order, but the tub was rusted junk, so I tossed it out. I noticed that the CJ2A and the M38 had the same wheel base. so I decided to do it military. I got a M38 jeep that had a good body ,etc. Bubba had intalled a 4 cyl Ford motor in it. Parted out the rest of the M38. The tub fit fine on the chassis with some changes in hold down bolt locations. I am now at the wiring step. An M38 harness has the large female plug for the light switches and the trailer plug, but no turn signals. The CJ2A has turn signals but no plugs for the lights and trailer. By way, the M38 had been converted to 12 volt including the light switch and the Cj2A already was 12 volt. Not sure what to do, I would appreciate your input. I'm not a mechanic by any stretch of imagination. Surprised I got this far. I've received great help from the forum before. It has been much appreciated. Thanks in advance! Jamsstuff

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Post by Cuz » Sat May 31, 2008 9:31 am

You need to give us more info.

1-Are you installing a new M38 wiring harness or trying to reuse and old one that came with the tub?

2-What are your intentions electrically. Have a 2A electrical system , an M38 electrical system or a hybrid? Option 3 will take an experienced hand to help you since it will not follow closely either wiring diagram.

3-Are you going 6, 12 or 24 volt?

4-How much of each model's electrical system do you wish to retain or use?

5-Which electrical components are you going to use? Ie, lamps (civvy/military), gages, starter, generator/alternator, distributor, horn and etc.

Hybrid wiring can really get a novice in trouble and seriously damage components and the jeep when not done correctly. One of the biggest pain in the arses to see show up in my shop is a poorly done amateur wiring modification. It is also one of the most common causes of vehicle electrical fires.
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C

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Post by Rich Saylor » Sat May 31, 2008 12:53 pm

Hi. The real question isn't necessarily how to wire the Jeep- but more, what you intend it to finally become. Since you've decided to mate a CJ chassis with an M38 chassis it's never be one or the other. As per the previous questions the electrical portion is a bit complicated, unless you intend to just start over. Not easy, but less confusing. M38 wiring harnesses are expensive- about $500 for the main part of the harness- but the rest is even more so. Then there's the question of the motor- CJ or M38, with original (expensive) 24 volt equipment, as well as the fuel/vacuum pump, which not only pumps fuel but powers up the vacuum system, that mainly operates the wipers but also the ventilation of the sealed military distributor, that also houses the coil, that generates heat. Lots to learn about, and so I suggest you get the manuals for the M38 on CD from Military-Media.com, as listed below, and the much clearer paper reprint of the parts manual from Portrayal-Press, also listed below.

From one point of view, since the complete Jeep won't really be an original military vehicle, it might make economic sense to have a lookalike M38 on the outside but a CJ on the inside, as well as underneath. Whatever the disadvantages, it'll be less expensive, as CJ stuff- by comparison- is cheap & readily available, as a friend of mine often says. If you make your own harness, remember that all M-Series military vehicles had all black wiring, with stamped aluminum tags to identify each circuit. The circuit numbers can be found on Olive-Drab.com, and even easier by googling "M-Series circuit numbers". Having a harness in colors is a dead giveaway that it isn't original.

The path you've chosen isn't for the faint of heart, more for experienced hands, but whatever you decide, it's bound to be a real learning experience!

In any event, good luck with your project.

The dealers, etc. below are a resource, but start with the manuals.

M38 Dealers/parts suppliers
(updated 23 Dec. 2007. Please provide update/correction info to Rich Saylor- saylor@redshift.com)

AJP (Army Jeep Parts) "George Baxter"215-269-5014 (expensive but good stuff)
Beachwood Canvas, New Jersey 732 929 3168 (also expensive but also good stuff)
http://www.boltdepot.com/ (nuts & bolts)
Rick Larsen stencils NY 413 269 0058/59 (fax) make sure you know what you want. There were lots of variations.
Midwest Military- M38 parts- 952 440 8778 These guys make lots of high quality repo parts
Military-Media.com Good (but not perfect) $20 CD with all the major manuals of all Willys Jeeps- MB/GPW,
M38(MC), M38A1 (MD), M151- but ONLY for Windows- willl NOT operate on Mac! Also, M-M has inflexible
return or order cancellation (no!) policy if you forget & order this CD for your Mac. Still, a good deal for PC users.
Hal Miller email kb1zq5@swbell.net vacuum, fording and fuel lines
Brent Mullins- M38 parts- (Texas) 979 690 0203
MVP wiring- harnesses & stuff- "Jeff Smith" 850 475 5030
National Band & Tag (#1631 metal tags, to match original 14 ga. small wire wiring tags. Other sizes available.)
New Life Upholstery- canvas stuff, repair- http://www.newlifecanvas.com/index2.html “Mona”
Portrayal Press (www.portrayal.com) (973) 579-5781 has good paper reprints of original manuals, at a price. Better
than M-M’s CD, but more expensive. The M38 parts manual (biggest M38 manual, over 400 pages) is $59, others
are much less. Their website of military manuals is most impressive! P-P is in New Jersey.
RAPCO- M38 parts- "Mark Dodd" Texas 940 872 2403 Good source for paint, and other stuff too.
Ron Fitzpatrick 541.582.4035 OUR WEBSITE HOST! Has lotsa stuff, good prices!
Rod Shaver data plates: scoutcarrod@cox.net 480 893-2201 Does good work!
Saturn Surplus (Pennsylvania) 717 692 9520
Scholer Restoration (near Sarasota, Florida): 813 677 7680 (vacuum lines, mostly correct but not all)
Star Electric- electrical stuff- "kevin" 502 877 0813
Surplus City (California)-M38 stuff, canvas stuff/repair- 818 767 3666 “Chuck”
Then & Now fuel pump repair: http://www.then-now.com/services.html Highly recommended!
Thomas & Betts- wiring stuff (HQ in Tennessee) 800-816-7809, fax 800 816 7810,
elec_custserv@tnb.com in Belgium: +32.235.98200 europe_inquiry@tnb.com
Vintage Wiring of Maine-wiring harnesses, etc.- "Joe Hall" 207 465 3431
Weebee Webbing- canvas goods- "David Pizzoferrato" 888 632 5684
Willys Acres- M38 parts- "Marcus" 705 835 5739 Ontario Province, Canada
www.wiperman.com/ http:// (vacuum wiper motor repair)

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re: M38 Wiring Harness Tricks

Post by whydahdvr » Tue Jul 08, 2008 12:05 pm

I just purchased a 1952 M38 that has a partially connected wiring harness. I'm having my local mechanic (trusted) work on the jeep as I travel a lot for work and the Army. What tricks might he need to know about reattaching the wiring harnes, cleaning out the carb, and other things to get it running?
I have been talking with Dave Uhrig and he recommended buying my manuals from Portrayal Press - they are on-order. But I know that manuals say one thing and practical field experience another. What tricks should I look for, be aware of, and share with my mechanic? Thanks!

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Post by petesilfven » Tue Jul 08, 2008 2:27 pm

The ONLY decent carburetor rebuild kit is the one sold by Army Jeep Parts or Midwest Military. It's around $50. Any other one is junk. The heavy spring goes on the accelerator pump diaphragm, and the light one is for the metering rod diaphragm. There will be two metering rods. Use the one that matches yours.
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Post by Rick L » Tue Jul 08, 2008 5:51 pm

The Carburetor Shop rebuild kit is decent also.

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Post by Cuz » Tue Jul 08, 2008 9:05 pm

If you have a "Real McCoy" experienced old non-smog vehicle mechanic then an occasional look in the manuals is all he'll need. If he does run into a brain tizler just have him pop up here or if he needs access to the many manuals not in the basic 4 manual set for the jeep have him visit out web sites where we store this data for member's free use.


If he is a fresh modern smog car mechanic and has never adjusted a set of points, rebuilt/adjusted a carburetor or worked on the old DC generator and voltage regulator he will need a lot of help.
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C

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