Wiring on my '52

[Gardy458]

First time posting but I've been lurking here for a while. I've had my 1952 for just over 2 years now. done quite a bit on it so far but since it was running and driving when i got it i have tried to keep from doing anything that would take it off the road for too long.

I'm finally to the point i think where i need to do some major work. First on deck is the wiring. when i bought the truck about the only wiring that worked was the charging and ignition. The lights were all either disconnected or spliced with wire nuts and all wire tags missing. I have since removed all lights and restored them, and am beginning to think about replacing all of the wiring.

Over the last week i have began tracing the wires and attempting to label everything before I pull the harness out to make a new one. it appears there were some dyslexic fellas working on this thing in the past. Im finding turn signals wired to the wrong side, and different front to back, lots of extra wires that don't seem to go anywhere even though appear to be part of the original harness, and random connectors that appear to be original but don't appear on any diagrams as well.

I think i will start this thread as not only a place to ask help from those that have more experience with these than i do, but also to share the progress and any information and resources I come up with.

A few questions I have right off the batt. What wire would you go with? Even though it wouldn't be "original" I was considering using the 14 ga Prestolite wire available from several sources, and stay away from the cloth stuff.

Second, does anyone have any pictures of them building new harnesses or harnesses laid out that they could share that i can use for reference.

Third, I have modified the trucks schematic to be correct for the solid state flasher that is installed, anyone with a schematic savvy mind care to check my work, ill attach it below.

 

[NDT]

Welcome, glad you decided to start posting now. My personal preference would be to do away with the metal shell connectors and go with the current set up for which parts are super easy to come by. I use Erik’s for this. Good luck.

 

[Karl kostman]

Gardy the metal shell connectors though very effective for their day there are much better ways to do it today! There are some folks who want everything as it was in the time the truck was built, I am not one of them! The quality of the wiring products today is so much better than even 10 years ago. My goal in wiring a truck is to do it once and do it right and never have to touch it again! Good luck with your project plan acquire and execute.

 

[Gardy458]

Gardy the metal shell connectors though very effective for their day there are much better ways to do it today! There are some folks who want everything as it was in the time the truck was built, I am not one of them! The quality of the wiring products today is so much better than even 10 years ago. My goal in wiring a truck is to do it once and do it right and never have to touch it again! Good luck with your project plan acquire and execute.

Thanks. I have put some thought into the connectors. still not sure on it 100% but im thinking i may play around with some modern connectors that i could maybe hide in the old metal shells. Realistically i could just use a waterproof butt splice under the douglas shells as i dont see too much need to have to disconnect them once everything is working as it should.

 

[Gardy90]

After 2 days of fighting, head scratching, and a few beers, I managed to get all of the light wires tracked down, tagged, and the rear harness pulled from the truck. It was so brittle I had to pull the fuel tank to get it out without damaging it too much. Going to finish up on the headlights and front turn signals this weekend and probably pull the truck out and set up a big bench to start building new harnesses.

 

[pjvargas]

After 2 days of fighting, head scratching, and a few beers, I managed to get all of the light wires tracked down, tagged, and the rear harness pulled from the truck. It was so brittle I had to pull the fuel tank to get it out without damaging it too much. Going to finish up on the headlights and front turn signals this weekend and probably pull the truck out and set up a big bench to start building new harnesses.

I've got a 1952 M37 also, along with two M35A2's. The M37 uses the Douglas metal connectors while the M35A2's use the rubber Packard connectors. Most of the wire I've run into on these military vehicles has been the 14 Gauge (Prestolite) M13486/1-5 wire. I can't recall running into any fabric-covered wire on my M37; it seems like most (if not all) of the wire used is the rubber-coated 14 GA I just mentioned. I bought a roll of this mil-spec wire and I use it for any rewire/repair jobs I need on these trucks (after checking to make sure that the circuit uses the 14 GA wire; as I said there are a few circuits I found that use 12 GA wire (which would be the M13486/1-7 wire)). On the M37 I tend to preserve the original harness design and connectors. My thought is they only put connectors on the harness where they were needed to aid in installation and/or to have a place to disconnect the wires to replace components. There may be better ways to connect things in your vehicle but a lot of times when you buy an NOS or replacement part for these old vehicles there is a good chance it will have the Douglas connections on them (or a part can be selected that has the Douglas connectors). I've found that if I do get a replacement mil-spec part (such as a replacement dash gauge) that has the newer Packard connectors then I have two options - make a short Packard-to-Douglas patch/converter wire or remove the Packard connector and put a Douglas connector in it's place. Both the Douglas and the Packard connectors use a crimpable center pin; if you have the pins it is an easy job to remove the existing pin, put the other connector pieces on the wire, and crimp on a new center pin. I either case I still use the M13486/1-5 wire. I know there may be other ways to remake your harness, but I really think that over time if you preserve the original design using the Douglas connectors rather than try to eliminate connectors or "jury-rig" it back together it will save you many additional headaches in the future as I previously mentioned. For example browse the parts offered by Midwest Military, Vintage Power Wagons (VPW), or Adirondack Dodge and I think you'll find the majority are built for the Douglas connectors. Also the crimp tools for the Douglas and Packard connectors will crimp both. If you re-use the Douglas connectors you can probably re-use all the Douglas connector parts; you'll just have to replace the interior pins on both sides of the connection. The bad part is companies like Daniels Manufacturing Co (DMC) used to sell the Mil crimp tool and the die for these pins; they still sell the crimp tool but I don't think they sell the die anymore (but the die and other crimp tools for these pins may be available thru an online search). If you do go with the Douglas (or packard) connectors make sure you use a small amount of dielectric grease when you put them together so they come apart later on. By the way you can add the metal aluminum wire identification tags when you make your new harness. They can be bought from National Band and Tag Company (www.nationalband.com) as their style 1611 Wrap-around Tag (M43436/3-1). You very carefully stamp the number on the tag and then install them on the cable by hand (no tool required). I think I bought 1,000 for $49 bucks a while back. Also Vintage Wiring of Maine used to sell replacement harnesses. Also VPW used to sell replacement harnesses but I think they are sold-out (Adirondack Dodge may still sell them). Also there used to be some listed for sale on e-bay. The easiest way to replace a harness is to lay it out and duplicate it by layout and length on your floor or work bench. Anyway I can't tell you how many time I've been rooting around in these old trucks trying to fix a wiring issue and praised the Lord that they had the metal tags on the wires so I could figure out what wire I had in my hand. If you want to discuss let me know how to contact you on your post.

 

[pjvargas]

Here' the MIL-SPEC on the wire.

 

[pjvargas]

I checked the Midwest Military site and Mr. Bizal sells a front and a rear wiring harness. Might be looked at as a bit pricey but when you factor in all your time and effort to not have to source the parts and fabricate it yourself it doesn't look bad at all. Plus it will get you back on the road very quick, or at least closer to that faster and will allow you to fix the next thing that needs attention. If you do get them I would call and make sure the harnesses support the turn-signal installation (if you have that or intend to put that on your truck).

 

[murf]

I just installed a solid state turn signal rig into my truck project and had to use douglas and packard to finish the job. I had disassemble some of the connectors and install different ones. Fortunately, I have the parts and crimpers. The biggest help in doing all of it was a can of spray silicone!

 

[G744]

Your schematic shows the early turnsignal system with a control box. Mostly unreliable, parts are unobtainium, and requires a special signal switch.

The second series uses the same signal handle and flasher unit found on new tacticals (a lot easier to) source.

I keep my trucks long enough that the OZ type rubber insulated wire starts aging and is prone to shorts in just a few years.

I've moved on to black style 1015 AWG 14 machine tool wire and make my own looms for my MV's. The tinned, fine-stranded, copper conductor is very flexible and solders beautifully.

It uses Vinyl insulation (that will outlast you and the truck), the outer diameter is so close to the original all the mil-spec Douglas, Packard, and Bendix connectors interface easily. It really looks stock when used with the number tags.

My last 1000ft spool from Southwire was around $180 delivered.

 

[QCI M37CDN]

Best thing to do is just go nuts, rip ALL the old wiring out, and throw it in the trash. Buy new harnesses, and install them according to the diagram in the manual. It doesn’t take long, I think it was about two hours to do mine, from removing the old wiring, to testing the lights. Doing it that way, you have everything according to the book. Makes life easier when you have an issue in the future, or want to simply replace something. I also installed a night switch in mine, so I can instantly turn off the power if something should go wrong. It’s readily accessible, installed in the passenger seat box.