M37 Barn Find

[jeffhuey1n]

Tail Light (Early Style Solid Red Lens), M561 Gamma Goat & M129A3 Trailer, 10920548-1 / AC-12337

Early style 3-bulb tail light with cast aluminum housing and composite red lens. Commonly used on the Gamma Goat and semi-trailers such as M129A3. P/N 10920548-1, AC-12337. NSN 6220008801237. Has 24 volt bulbs installed. Item is new/unused. Factory original part, made in USA by Aurora...

www.eriksmilitarysurplus.com

Those do look nice!

 

[jeffhuey1n]

Been working my way through the new (old) wire harness. Even though it’s a used harness, it is in remarkably good condition. Some of the connections had to be replaced because of deterioration of the connectors but over all, it’s worth every penny!

 

[M-37Bruce]

If I can get to the shop today, I'll try and snap a pic.

 

[M-37Bruce]

 

[M-37Bruce]

 

[jeffhuey1n]

View attachment 824741

That does look nice!

 

[jeffhuey1n]

Well wiener schnitzel! The dingo coil is broken. Literally. The top of the coil is broken all the way around. Must be some reversal of gravity preventing it from falling apart. Anyway, I have a coil stashed away and I dug it out. The old one required an external resistor. The new one (NOS) is slightly smaller in circumference but I’m pretty sure there’s nothing wrong with it. Not sure how to test for serviceability. I’ll post a couple pics sometime this weekend. At least I have some good things going my way. I had an in-line electrical fuel pump plumbed into the system but I didn’t really like how much space it took up. The one I’d originally wanted to use finally showed back up. So, in the midst of switching the electric fuel pump and removing the air pump for the air horns, I’m finally seeing an end to my electrical nightmare.

 

[jeffhuey1n]

Both tail lights installed. All front lights are installed. Started work on the turn signal but hit a stoppage. There’s a broken wire (blue) inside the mechanism. Not sure how I’ll fix it yet but watch for the mushroom cloud. It’s going to be a pita to fix. Got the replacement coil installed as well as the ballast resistor. The 12 volt voltage regulator is installed. Now I need to wire everything up. Also been going through all the old wiring. Found some connectors that needed salvaging. Each day is a little bit closer to completion.

 

[jeffhuey1n]

Things are progressing. Got the coil, ballast resistor, alternator regulator and light control installed. Began laying out the repaired wire harness. One change to the plan comes as a result of the V-8 installation. The large voltage regulator is not used. A simple alternator regulator with two connections handles the task. One issue that came up was how to wire the engine and gauges since they aren’t stock M37 parts/diagrams. After some internet search, I found a wiring diagram for 1962 to 1965 Dodge light trucks. In addition is the engine itself. Knowing which engine was essential to properly wire everything up. Sorry, only a couple-three pics today. I’ll try to have some for the next post. I found these two electrical items attached to the steering column support. Maybe they are some kind of ballast resistor?

 

[M-37Bruce]

I have never seen anything like that, the porcelain does have ballast look to it?

 

[jeffhuey1n]

That’s what I thought as well. If indeed they are ballast resistors (BR), I might have to use one. While installing the wiring, I tightened the screw on the original BR just a bit too tight and it went crack! I’ve superglued it, not sure if it’ll work. I also have another ballast resistor in my hoard. It has 4 blade type connections. The two sets aren’t interconnected. I ohmed them out and there’s two different readings. The cracked BR ohmed out at 2.7 and the 4 way ohmed out at 1.8 and I can’t remember the other reading. I’ll check them out again and add that to my post. Not sure what the reading is supposed to be. Do we have any ballast resistor experts on board this site? This truck is a troubleshooters dream! Good thing I just happen to have some slight skill with these types of conundrums.

 

[hndrsonj]

What original Ballast Resistor are you talking about? I don't remember one.....

 

[jeffhuey1n]

What original Ballast Resistor are you talking about? I don't remember one.....

It’s part of the V-8 conversion done by the previous owner. Sorry for the confusion. What I can’t quite figure out is whether or not some of this stuff is necessary. There was a bunch of wiring in the dash and pretty much everywhere else on the truck. It’s difficult figuring what’s a keeper and what’s just so much junk. I’ve put the wiring diagram for the truck that donated the engine compartment stuff. It shows the ballast resistor as it fits in the wiring.

 

[jeffhuey1n]

Didn’t get anything done today, and probably won’t for the next week. Weather has taken a arctic turn for the worst. It’s currently snowing with a temp of -6 degrees Fahrenheit. Wind chill is -20.

 

[M-37Bruce]

I'll have to check mine tomorrow, when I did my wiring I replaced a ballast resistor, rectangular, anchored to the wheel well, simple little ditty, 4$ at NAPA, seemed purty generic.

 

[jeffhuey1n]

Well I’m stumped. I’m wiring up the engine. Got the coil, voltage regulator, ballast resistor installed. I was looking for a diagram the could help me figure out the starter relay. I’ve searched for the relay that came with the truck but I can’t find it. There’s seems to be only 2 relays for the early 60’s V-8’s. A square one and a round one. I am starting to dislike rewiring jobs...

 

[John Mc]

Well I’m stumped. I’m wiring up the engine. Got the coil, voltage regulator, ballast resistor installed. I was looking for a diagram the could help me figure out the starter relay. I’ve searched for the relay that came with the truck but I can’t find it. There’s seems to be only 2 relays for the early 60’s V-8’s. A square one and a round one. I am starting to dislike rewiring jobs...

I thought the starter on an M37 was activated directly by the foot switch, with no relay involved?

 

[jeffhuey1n]

I thought the starter on an M37 was activated directly by the foot switch, with no relay involved?

On an unmodified M37 you are correct. The previous owner removed the stock engine and replaced it with a commercial Chrysler 318 poly engine made between 1957 and 1967. As such, everything from the donor vehicle, the engine, coil, ballast resistor, voltage regulator and starter relay and a bunch of other stuff. My memory ain’t the best on a good day so remembering the full layout is difficult. I remember removing a component that kinda looks like the starter relay from early 1960’s Dodge trucks.

 

[John Mc]

OK. I misunderstood when you said "I’ve searched for the relay that came with the truck". You weren't talking about the original truck.

 

[jeffhuey1n]

OK. I misunderstood when you said "I’ve searched for the relay that came with the truck". You weren't talking about the original truck.

Correct.