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Thoughts on using stock harness vs full replacement


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7:06 PM
Jul 24, 2013
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Do most of you guys fix the stock harness or gut the whole thing and replace it? My car has been off the road for 34 years sitting in a field. Once the motor is finished and I get floors in it, it’ll be time to start on this stuff. My dad has used the factory harnesses in his 60s Toronado, eldorado and my brothers jeep trucks with pretty good results…however for those vehicles reproduction parts are more scarce. I know the insulation ages, but is it worth testing first or just replace it? The last thing I want is a fire. I do plan on doing power tour at some point in this once it’s road worthy, so reliability is important.

Would installing a painless harness be a better choice for my application? Or is there another brand people prefer a true reproduction with a more factory look. Clearly I’m not going for all stock…and the car will be driven a good bit.
I reused my dash harness, but I cut off every wire an inch or so back from the bulkhead and crimped new ends on and used a new bulkhead connector. Also replaced my headlight switch connector and 6" of wire, as that's another spot that likes to "cook" and harden wires on these old boats. Other than that a good inspection of all wiring for hot spots and hardening and there's no reason not to save 500 bucks! Engine compartment wiring is usually heat soaked and cooked, but that harness is cheap.
As long as the harness is not melted or butchered you can fix it up. I pull each wire one by one out of the insulator plugs and clean each terminal and crimp each one.
I use original wiring when possible. If the crimp is good between the wire and terminal then don’t mess with a good thing.
Baby Blue still has the original harnesses, with exception of some new wiring to the passenger side head light in 2013. However, the car was never left in the elements or rodent infested.
The wire does not deteriorate, but the connections can from corrosion. As others have suggested, fitting new terminals is a good fix.

As for new harnesses........
Painful might be more accurate than Painless....
Rewiring a stock style system is a piece of cake. It takes some research time to find the correct terminals but, they are available. Wire is easy to source if you don't try to buy traced wire. I can recommend a set of Astro crimpers for terminating. And lots of wire loom.
Ask yourself this, would you rather have a harness that's held up for 50 years or one made from Chinese wire with who knows the true copper content and an outer jacket that will probably fade and crack in a few years.
It all depends on the condition of your existing harness. Most of my restorations, I just had to rewrap them. @dadsbee advice is tops.
Rewiring a stock style system is a piece of cake.
I've never shied away from anything mechanical, or electrical - except rewiring a dash! In my opinion there are just too many junctions and connections to keep it straight. And one error will have you chasing your tail forever. The dash is where everything comes together and is a complicated harness. Engine and front end - piece of cake, interior and back end, same thing. But the dash ... buy a reproduction unit and be done with it. Everything else can be done with parts store wire. And I like Dadsbee's idea - since I'm no longer using the stock bulkhead connectors.
I always rebuild the stock harnesses. It's pretty easy to do, you know it fits and you don't have to wait for parts that might or might not fit to show up. I would routinely harvest harnesses from assorted old Mopars to use for parts when needed as well. Sometimes you need connector blocks and plugs. PICO carries whatever terminals you require.
Part of your sitch is being in a field for decades. Heck, had my tractor in a closed garage over one winter and mice chewed up a wire, same thing with my FIL’s car. Yep, do a thorough check of the wiring to see if any has been chewed on, not a fun chore. As posted, connections can corrode, light sockets, and replaced many connections. One time the fuse block was surprisingly skanked and my ride never sat outside. Found connections touching each other and part a that was likely from later adds plugging spades for stereo and such. Good tips about harnesses as I had bought a jina chit one once and should a been more careful what I was buying, was rear harness. The bulb sockets sucked, one broke/shorted out; ended up reinstalling the original ones after cleaning those.

Good luck on this chore – lots to look at.
If you plan to add other electrical options like fuel injection, power windows, a/c and so on then use a painless performance harness. They use the original color wires and it's not that difficult but is somewhat time consuming. There are always problems with the factory bulkhead connectors and painless eliminates that. If you don't want to add electrical accessories then I'd go with a factory style replacement harness. I think they are available at Year One
The harness is my 70 Charger was butchered, I bought the M&H from Year One, was worth the investment for me.
Very happy w/ it so far and might buy a few more for my other cars.
There are water resistant bulkhead fittings available far superior to OEM units.
When I wired my car I didn't see any. Also I added a/c, fuel injection, power windows and locks and remote start. So I needed more fused circuits
As mentioned, the under dash harness usually survives OK if it was not butchered or melted before.
The under hood harness is not worth messing with, usually the engine heat and exposure to the elements really makes a mess of the harness.
What you want to see is the insulation is still soft and not cracking, and that the copper wire is still shinney under the insulation.
Cutting off the old corroded terminal ends and stripping the wire to good copper to re-crimp new ends on might be OK if the wire is not badly corroded.
I would check the condition of the fuse block. See if it will clean up. I usually start with a tub of water mixed with dish soap and lemon juice.
The soap helps clean the dirt and oil off, and the lemon juice will remove corrosion from the copper.