Wiring harness options

[Bennyt]

While I have re-wired Squarebody's with aftermarket kits, I'm not sure that an aftermarket kit is necessary as they are still somewhat modern. On older cars with fabric wrapped wires, glass fuses, 6v, generators, manual everything; a complete re-wire is more of a necessity.

Moving on..
I've used both and both are excellent. I will say that I prefer the AA a bit more than Painless but you can't go wrong with either. I know the kits are $700, but if you look around and wait for sales, you can typically get 10-20%. You will also need to budget some money on quality crimpers(Packard crimpers are $180), wire tape(not electrical tape, $10 on Amazon), and different sizes/ types of conduit/ sleeve($40-50 for various sizes, and shrinkwrap($20). That can add up quickly. I also find it handy to have a Packard connectors kit($50) that you can use to wire in accessories such as lighting, mirror's w/ signals, trailer hitch, etc. $700 turns into $1000 very quickly.

Also, before I wrap/ term anything...I typically lay it out and zip-tie every 6-12" until I figure out routing. I actually bought a role of double-sided velcro that's pretty useful and can be repositioned easily.

 

[ali_c20]

Since you have used both which one would you recommend?

AAW is more $ but has more connectors so you don't have to get new or reuse connectors.
Painless is cheaper and customizable and has more circuits. I will use weatherpack connectors for my c20 built with a painless harness.

AAW requires/recommends special crimping tools which are ~150$. I didn't buy these tools but crimping the connectors the right way was a pita.

I would recommend Painless if you want to customize some of the wiring.
AAW if you want to be close to stock look and function.

Painless
AAW

 

[Bloodhound1981]

AAW is more $ but has more connectors so you don't have to get new or reuse connectors.
Painless is cheaper and customizable and has more circuits. I will use weatherpack connectors for my c20 built with a painless harness.

AAW requires/recommends special crimping tools which are ~150$. I didn't buy these tools but crimping the connectors the right way was a pita.

I would recommend Painless if you have want to customize some of the wiring.
AAW if you want to be close to stock lock and function.

Painless
AAW

I've used Painless and AAW. I definitely prefer the AAW kit.

 

[germando]

I just rewired my daughters 73 454 with the aaw kit. Best decision ever, biggest difference I see between painless and aaw is that the aaw kit includes new light sockets for everything and the painless does not. Both kits are good, I had originally ordered the painless, but cancelled as the next day showed back ordered for 2 months. Ordered the aaw and will be using them from now on

G

 

[Dleslie212]

I'm in the middle of installing a Painless kit now. I am terrible at electrical, but the instruction book is priceless in helping me. If you look at my posts, you can find an installation journal I've been working on with progress

 

[MikeB]

Having done four different brands of kits on several vehicles, I'd say Painless has the best documentation by far, but American Autowire has pretty good docs, tends to use larger gauge wire, and has fantastic tech support. I used an AAW Power Plus 20-circuit universal kit on my 82, but would go with the specific kit for square bodies if I had a do-over.

I did my 69 C10 earlier this year with a vehicle specific AAW kit. I was fortunate to have bought it in 2021 before multiple post-Covid, inflation-fueled price increases, and got another $50 discount from Summit! Win, win! I wasn't crazy about the fuse panel they used, but I think it fits perfectly into square bodies. Maybe member "justhorns" will chime in on that.

I'd suggest you stay away from no-name or private label systems sold by Jeg's, Summit, Speedway, etc. if you value tech support and documentation.

 

[CTxK20]

Would using the painless instructions and documentation as a reference but using the american autowire kit be a good idea?

 

[MikeB]

Would using the painless instructions and documentation as a reference but using the american autowire kit be a good idea?

Follow the AAW instructions, but you can use the Painless doc if you need more detailed information. I actually referred to it a lot when I installed the AAW universal kit on my 82. But in fairness to AAW, it was their universal kit.

Check this out. 164 pages! https://www.painlessperformance.com/Manuals/20205.pdf

 

[Dan Brown]

I'm currently restoring a 1974 K10 which I'm converting from a carburetor to TBI. I have built my own harness by using new wire and connectors and also cleaning up and using some of the original harness. Much cheaper than paying 300 to 500 hundred bucks or more for a new one.

 

[Donald]

I too like American Autowire

 

[MikeB]

Here is something you'll have to deal with if you use a universal kit. It's the instrument cluster connector. You can always splice into the old one, but then what's the point of installing a new harness? This connector and terminal kit is Ron Francis Wiring #PC18.
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[justhorns]

Maybe member "justhorns" will chime in on that.

I don't really like any of the fuse boxes due to LOCATION. If you think its hard to change a fuse down there, How about installing the thing. That said, its really not painless to install any of them. Doing a 70 ford right now with AAW. But the results are a better than new harness if installed with AAW and Heat shrink, crimp fittings.AAW provides the connectors and I have already had the special tools. It can be relatively clean work, except when a truck sat in the field for 7 years and filled with dust and mouse droppings, like this old ford.

 

[Rick R]

I used AA on my 73 c10 build. It was the exact replacement wired from the original diagram. I was/am very pleased with layout. Everything fit perfectly. Their customer service is very knowledgeable and helpful. Ive never used another so nothing to compare it to.

 

[GTX63]

How much cheaper do you think a good donor truck would be than a new wiring harness?

If you have the room and an understanding wife and neighbors, a donor is priceless. I recently pulled the underhood wiring from a donor 79 for a butchered 83. Everything worked out just fine.
I cannot count the number of times I needed a part, and the options were A. immediately pull it off the truck behind my pole barn, or B. order the Chinese variant and wait x number of days.
If you can't keep a donor truck onsite for long periods, take what you need, sell as many parts to recoup your investment and then scrap it. Win win.

 

[MikeB]

How much cheaper do you think a good donor truck would be than a new wiring harness?

Maybe less expensive, but keep in mind that it's another old truck which may have some issues with connectors, worn-through insulation, etc. And you'll find lots of different wiring schemes for the various instrument panel configurations. Also, engine compartment wiring will be different based on engine type, A/C vs. non-A/C, carb type, and more. If you have a donor where everything is the same, that would be unusual. If you do go that route, I'd still suggest using new ignition and headlight switches.

When I first went from a 250 six to a 350 in my 82, I was able to use the OE harness. However, I spent a lot of time lengthening, shortening, adding, and removing various wires. The 1982 factory wiring diagrams and me spent a lot of time together!

Due to some rust on the fuse panel connectors and some flaky bulkhead connections, I later ended up going with the AAW Universal kit I mentioned earlier.