I am starting this thread in the hopes that I can begin to understand the black magic mystery that is automotive wiring, and perhaps to help others on their journeys as well by getting info into one location.
Project is a 1976 Dodge Power Wagon.
The factory bulkhead connector and ammeter in the dash are known issues on these trucks, as they tend to melt down, let the smoke out, and then torch the truck.
I would like to solve this by rewiring the truck, replacing the factory bulkhead connector with a bayonet/amphenol type connector, and routing/cleaning up the harness into sub harnesses.
I have SO. MANY. QUESTIONS!
We will start with the first one- Using an American Autowire harness, how many circuits do I need?
Carbureted fuel system, will be adding electric fan and A/C at some point, and the ability to add a winch and auxiliary lighting is a must. I would also like to keep the factory fuse panel location on top of the dash in the glovebox (that way I don't have to stand on my head).
Duster and all you other wiring gurus, help me out?
Is this a 'rod or other highly modified truck, or is this more of a stock use case vehicle?
because unless the custom is something you want, you can probably just get a brand new stock harness and replace the whole thing. That would be way easier than reinventing the wheel.
Can you get an original wiring diagram?
Especially if you can get a digital version of it- then you could edit it. Well, you can at least erase the stuff you don't want anymore.
But I also think a stock new harness would be a solid way to go if you have one available.
If that isn't an option- if you get a replacement- do those even have bulkhead connectors? Or do they just pass through?
I'm curious what folks will recommend a bulkhead connector and mating connector. The parts I'm used to for this are normally used in aircraft (because that's where I'm at) and while they could totally work in a car, they're not cheap. And kind of heavy due to the materials used. I sometimes see folks just use a big grommet and then pack the area with stuff that's kind of like RTV when dealing with automotive environments, and that works I guess. But it doesn't seem very nice or neat or easy to maintain if you have to make changes there.
I believe Chrysler used in-dash ammeters where all charge current went through a not very large conductor path which is where the fires comes from. Wire isn't really up to the task from a basic circuit analysis and then add years and corrosion etc and it's a bad time. Really curious what Mopar folks are doing to deal with this. Off the top of my head, splicing the meter out of the circuit entirely and keeping that power flow 100% in the engine bay would be the first step. Next step would be modifying the cluster to get ride of that part of the gauge. I think usually the ammeter is part of the speedo but your truck may be different; removing whatever bits correspond from the gauge face and then covering that with a cheap small LCD voltage gauge might be nice. Or a color changing LED attached to a little controller and just having that showing where the ammeter used to be would work though it wouldn't be as neat and obvious. I had one on my old motorcycle and it was maybe $25 at the time.
Really depends how much work you want to do and how much you want to fix/change. Hopefully you get some good suggestions in this thread.
EDIT: I found this and at first glance this seems really good all around; https://www.diyautotune.com/product/weather-pack-22-position-bulkhead-connector-kit/?gQT=1
In reply to everybody:
A stock harness isn't really the best option in my opinion. Stock wiring on these trucks is kinda crap. No headlight relays, ammeter in the dash (there's a way to bypass the ammeter and add a voltmeter), buss fuses, and a bulkhead connector that is known for resistance issues. To top that list of garbage off, these old Dodges don't really have the best aftermarket support, and stock harnesses are pretty much impossible to find.
I believe it will be easier to build out a universal harness with the options I want from the get go. It'll allow me to run relays for lights to minimize current through the switches, switch over to blade fuses, and get rid of all the brittle connectors from the 70s.
Is there a website / app etc that helps you build a wiring harness ?
One that you can pick the wire color and gauge , and "build" a harness for each circuit .
In reply to californiamilleghia :
I'm wondering if the installation guidance provided with kits from companies like Painless Wiring could be used as reference material. Look at the references, draw your own out, update as needed when specific components are selected like when looking at an actual cooling fan for amperage requirements for wiring and circuit protection.
NOHOME
MegaDork
3/6/25 3:43 p.m.
I am a big fan of being able to service/troubleshoot wiring years past installation.
Best and easiest method is original or repro restoration harness. Best bet if u have never done this stuff.
Cheapest wiring kit are the eBay universal kits. I find them no fun to revisit a year later cause they are cheap and hard to read wire tags.
If u are cheap but handy, you can harvest. A wiring harness from a car from the same manufacturer and strip or add the bits u need. This allows you to use a factory wiring diagram to trouble shoot in the future.
In reply to NOHOME :
Repro wiring harnesses don't exist for these trucks.
I could find a factory diagram easily, but that means building a harness from scratch...
In reply to Recon1342 :
If you want to update the wiring and make changes from factory, and there is little to zero change of buying a complete harness from either Chrysler or the aftermarket, what else can you do besides build a harness yourself besides hiring someone to do the same for you?
Recon1342 said:
In reply to NOHOME :
Repro wiring harnesses don't exist for these trucks.
I could find a factory diagram easily, but that means building a harness from scratch...
No, you can use the diagram to figure out what wiring kit you need to rewire the car. Use the diagram to know what components you need to keep, which ones you want to take out, and figure out how to add components.
In reply to alfadriver :
Ah, gotcha. That makes sense, thanks!
My truck project is just about the same as yours. 74 Dodge Power Wagon, 4bbl, 360, w/factory AC.
You seem to be aware of the electric issues with these trucks. I read about the issues (heater, ammeter, etc) on a site called DodgeTalk. I have kept the factory fuse panel in the glove box. I also plan to add - electric fans, auxiliary lighting, etc.
FWIW, my plan is to keep the factory wiring (mine seems to be in good condition) for the basics. And do the upgrades/fixes I came across on the Dodge site. For additional electrics I got a relay / fuse box out of a Dodge minivan. I may also move a factory item or 2 on to the newer box. In particular items that would be better off on relays (headlights).
A Couple of Suggestions:
Make a list of what needs to have power
Start with a clean piece of paper and draw the basics:
Battery to Starter
Switch to starter
etc,
etc
