Technical Full car replacement wiring harness

The field car needs the full wiring harness replaced, and I do not like the look of a painless harness but they are affordable. The OEM from Dennis Carpenter and C.W. Moss are my style but they are high quality and priced appropriately. The Special only has one tail light and no turn signals so it is simple; why is building a car take so many choices?

 

I'm also curious what people are using to rewire a whole car, I've got a couple with very old fabric covered wiring that would benefit from a redo. I feel like a fuse panel is easy to hide and the wiring itself would look period enough covered in fabric tape, just wondering what others have done.

 

haywire just panel ? different look than painless

 

I used a Rebel 9+3 kit when I rewired my '39 p/u and converted to 12 volts.. High quality, fair price, and good tech support. But first question, 6 or 12 volt. Don't use a universal kit for 12 volts if your ride is 6 volts. If it is Rebel makes a 6 volt kit last I knew and IIRC they are an Alliance vendor.

 

I used American Auto wire. I covered all exposed wire with asphalt fabric loom from Tons for that vintage look

 

I've rewired 3 cars using the Rebel 9+3 kit over the past 15 years or so. It was easy to install and has held up great. I've always heard support was great for them also, but I never had to contact them. I also used the asphalt coated fabric loom for the wires under the hood.

 

I've used Rebel 9+3 a few times worked on other brands and made my own. If your looking for price and quality Rebel is good (8 circuit up to 21 circuit). Finding cloth covered wires is pricey but worth it if you want that look. If you have wire already and just need a fuse box, I've used Blue Sea marine panels or built stuff from Del City.

For covering I've used Asphalt covering (remember to load extra wires into the covering in case of future upgrades), I've also used split loom that wraps around itself for computer cables (not the corrugated junk) and also good old friction tape. The computer stuff is plastic and stuff from McMaster Carr is hi heat material.

All depends what you want/need

 

Ive just spent a couple days redoing all the wiring inside my coupe, still have to do from light switch to headlights and taillights etc. It was actually a project that started with just trying to fix one thing and on it went. Im new to doing anything like that but its relatively simple to do from scratch if you take your time, buy a few quality tools and read up on some of the great threads on here. The other option is a complete harness as you have discussed. If doing it yourself here are some learnings from someone having done it for the 1st time myself - hence Im no pro.

1. Pull the drivers and p***enger seats as it makes it MUCH easier to get under the dash - I didnt and on Day 3 was wishing I did.

2. Do one circuit at a time. Id start with the starting circuit so you can at least move the car quicker than not. Small wins are good and always good to know your car will start lol

3. I installed a 40amp circuit breaker inside the car on the constant power from the starter prior to the 1st fuse box (separate box for switched power that ran from 1st fuse box feed to ignition switch and then back to switched fuse box). I couldnt get a split 12 circuit fuse box. The circuit breaker is very is very convenient for isolating power when wiring. Used 10AWG wire for the feed hence the 40amp breaker.

4. Buy some quality tools including wire snips and a good set of crimpers. Id use mine to hold the terminal then feed the wire into it. You dont need to break the bank and I really like my ratcheting crimpers from Bezos Inc.

5. Use uninsulated terminals and heat shrink. I also put clear shrink wrap loose on all wires so I can label them and then clear over the top. (Not needed with pre made harness).

6. Loosely cable tie wires together so you can feed in the extra one or two you forgot.

7. TAKE YOUR TIME. When it doesnt work redo it. They are only terminals and you will have a lot of them.

8. Dont panic when a circuit doesnt work, you probably havent reset the circuit breaker or added a fuse to the fuse box.

9. I used one dedicated ground for all in car grounds. Grounds are linked via the fuse box to it. Should make fault finding easier.

10. Leave wires longer than you think you need. Much easier to trim them add a little bit....

Have a beer at night being happy you learnt something and improved your car

Im somewhat confident (perhaps misplaced) I could wire a car from scratch now but for convenience and reduce time working on my back in a small coupe think it would be a Rebel kit or similar if I was to do that.

I do have a speedway wiring kit but it all looks a little light on so wont be using it.

 

I’ve used a couple EZ harnesses and a Rebel. No issues with either brand. I’m leaning towards the Speedway cloth covered harness, once I get to that point on my current project.

https://www.speedwaymotors.com/12-C...ess-Cloth-Covered-Automotive-Wire,451218.html

 

I’ll check out the rebel 9+3 harness too. Wrapping with an asphalt looks correct and that would hide modern wires nicely

 

Another vote for the Rebel 9+3. My Model A was my first full harness wiring job and - with a bit of help from their tech support and some HAMB thread research- it went smoothly.

 

I used Kwik Wire on my 49 Buick. No issues at all, and everything worked first time.

 

I used an EZ Wire kit on my '47 Buick. I bought the cheaper one from a dealer at a swap meet. It functions as it should, but EVERY wire is black. They are printed on them what it goes to, but color coded would be easier. I'd use their products again, just not the all black wires one. I might just use a fuse box and wire the rest from scratch on the next one.

 

Why do you think they call it Haywire.

 

I recently rewired two cars. On my own car I used a Painless wiring kit. Very easy and good quality. I did a 442 for a guy and he bought an American Autowire. I found it to be much harder to install. The Painles kit gives you the main panel with all wires attached. The American Autowire had the wires separate from the main panel. You must attach each one at a time in a ferule with a small screw on the panel. I found that much harder to deal with and also a potential problem spot from loose screws and corrosion. Just my opinion.

 

Driven wire works is really nice and compact (smaller than all teh other options especially in height). does not have the wire attached, which i like. Used by Brizio and south city and others. Super versatile and made in the USA. Also can get all black wires kit with lables on wires which is kinda cool. also a cloth option i think.
drivenwireworks.com
Driven WireWorks

 

I have done 2 EZ Wire kits. The quality is good and the cost is reasonable. The instructions focus on HOW to wire the car. I think a complete novice could easily wire a car using GM electrics. Just follow their instructions and hook up the labeled and color coded wires as they tell you to. My first project used all aftermarket GM style components and it was easy.

Doing a Ford based system requires a bit more experience. The kit's design and their instructions are GM focused and the Ford diagrams are pretty generic, not telling you specifically where to connect each wire. My second project used a Ford column and its incorporated light and ignition switches plus a Ford 3G alternator. I ended up having to design the under dash and charging circuits from scratch based on the Ford switches to figure out where the kit's wires connected. Not really hard, but probably beyond a novice's pay grade.

I would recommend these to anyone wiring a GM system. Ford and Mopar guys need some experience and patience, but can end up with very nice results with a little bit more work.

 

I'll use EZ wiring on my current '40 p/u build, as it will be the eighth kit I've used of theirs.
The first wiring kit I ever used was EZ Wiring, so the familiarity of it, and lack of any problems keeps me coming back.

 

I haven't used this kit and haven't wired a car in a few years. I am going to buy the speedway harness and use it on my car this winter. it seems to be the best option for a cloth wrapped harness I can find.

 

^^^^ I bought one of these for one of my Buicks. The kit is really nice and comes with good instructions. On the downside, the rear wiring section is only 12 feet long and not long enough to go from under the dash to the rear lights. I bought replacement cloth covered wires in 16' lengths from Ton's Performance and swapped them. The color codes were close enough on the new wires.

 

Great to have another thread with real world experience, but OP you are moaning about having choices?
And cost of a researched, fabricated, correct harness being too much?
Sigh.

 

Guess I'm old school. I just start running wires to where they go and connect them. When I'm done there are no left overs and none too long or too short. But, I was doing this long before kits were available so I don't know any better.

 

You answered your own question.
You want to go the original style harness. I think this answers more than you think about the whole project. More on that later.

The original harness has lots of merit in its construction and simplicity. Some stuff you likely already have on the car and it’s probably good or needs cleaning. (Light breakers, switches and senders and blocks )

For the original style harness, you can get the main under dash harness and make the rest.
Or get the under dash and engine harness.
Or…completely build a the factory harness.
The body harness is pretty straight forward and if you research suppliers, you can the appropriate wire and connections.

Crazy Steve has excellent posts on wiring cars. His posts on automotive wiring are the best articles I’ve ever read on the subject.
Period!!!
Read Crazy Steve’s stuff.

For what you really want, you are going to have to modify any mail order harness. Most of those kits have nothing for the starter ****on type system and lot of stuff you don’t need.
Most are too light.
Most use cheap connectors.

To do a 1941 right…..
You need to use the bullet connectors especially if you piece in pre-made factory style harness pieces. Some taillight ***emblies come with male bullet connectors.
Don’t throw the old harness away. You may enough for a pattern. You can cut off, clean up and use some of the old connectors.

Get the 1941 Shop Manual.
Get a wiring diagram for the 1941 Ford. Van Pelt may have a diagram.

Get a some pro quality strippers.
Get some pro quality wire crimpers.
When making a harness you may have to use insulated connectors and wire ends. These hard plastic ends need to be removed, either cut or melted off.
The crimp goes on the solid side. The split side of the connector rests on the round side of the crimper.

Some like to crimp and solder.

A 6 volt harness can easily accept 12v. A12V harness cannot function in 6V.

I would build it to 6V specs.

I think you really want a nice 41 Ford.

You have a Flathead block bored and ready with no cracks. You are way ahead of the game.

Build this 41 up nice with the Flathead. You can have such a nice car. It just takes time.

It what it is and what it is ain’t bad.
It’s always, always easier to build them back stock, or close to stock and then go from there.

 

@F-ONE brought up some good points. The bullet connectors Ford uses are a special size, .150" IIRC. I bought a bulk package of 100 each (male and female) from a vendor, but I will need to look the package to see from who. If keeping the car 6V, most circuits will require heavier gauge wire than most aftermarket kits have. Companies like Rhode Island Wiring make the correct replacement wiring kits but are pricey.

 

Yep, @F-ONE broke it down. I will also mention that the stock harness offered might include the other tail light and turn signal wiring since almost everyone would upgrade to those. If so, it will be extra to remove those or build without. They are not going to be cheaper unless they are already building them that way.

 

Working around the single tail light is easy. Just connect brake light switch output to left brake light wire of aftermarket kit of choice and disregard all the other wires involving signals.

 

Do those wires strip like conventional wire or do you need to cut with a knife?

Do you know what sized wires are in the cloth kit? I have a standard Speedway kit in a bag and the wires look pretty thin.

Thanks!

 

^^^^ Cut the outer cloth with a razor knife and strip the rest with a wire stripper. The wire gauges are appropriate mostly for the load intended @ 12 volts. The original rear section was 14 gauge, and I upgraded to 12 gauge when I swapped in the longer wires. I also upgraded the alternator wire from 10 gauge to 8 gauge.

 

I’ve done two complete rewire jobs from scratch using EZ wiring kits. Decent quality kit, the instructions could probably be better but you can piece together the missing info from online resources and of course the HAMB

 

^^This is true^^
I'm glad I had the old "How to Wire Your Street Rod" book for reference. It breaks down in easy to read & understand terms (and drawings) for GM, Ford and MoPar applications.