Wire Harness... what to do?

mopar_4life

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Hello,

So my wife got me this book for christmas and its a project planner for a car restoration and its pretty cool. It breaks everything down into sections and allows you to track everything done to the car and the want list. Well theres an electrical section and it got me thinking...(also seeing the tread about all of these burnt up cars lately). Should I replace my complete wire harness? Perhaps something universal or try to have mine reproduced.


Thanks

Eric
 
Not trying to sound like a jerk, but - does it need to be replaced? If so, yes, if not, no.
You should certainly go over it and check to see if any individual wires need to be replaced.
 
Hello,

So my wife got me this book for christmas and its a project planner for a car restoration and its pretty cool. It breaks everything down into sections and allows you to track everything done to the car and the want list. Well theres an electrical section and it got me thinking...(also seeing the tread about all of these burnt up cars lately). Should I replace my complete wire harness? Perhaps something universal or try to have mine reproduced.


Thanks

Eric

In addition to inspecting it for hard/cracked or overheated wires, I would make sure all connection points (male/female) are clean/bright (low resistance). Unless a wire is pinched or otherwise compromised along its travel, 99% of problems will be at each connector.

Even with this, I'd mostly concern myself with high-amp circuits like the ampmeter at the bulkhead, blower and A/C clutches, headlights. The real danger for fire is slowly overheating a wire, whereas a dead-short to ground with blow a fuse or fuseable link.
 
I wouldn't even consider a universal harness. They are great for street rods, but I've never seen a good installation on anything else.

Here's what I did with my 53 Windsor.

First, I removed the individual harnesses. This is a simple car compared to anything new, but it really isn't too much different from my 70 300 when you break it all down.

Do one at harness at a time. I can't stress that more. Do the easy ones first.

Get a piece of plywood and some finishing nails and lay the harness out like this:

2012_1204Stuff0003.jpg


Take a bunch of pics and make notes.

This is the way they make harnesses in the defense industry among others, so it will work for your car.

Cut the tape wrap off and replace the wires one at a time. You'll have to figure out the terminals etc.

Wrap the harness back up with non-adhesive electrical tape just like the factory did. Don't use regular black electrical tape with adhesive except at the ends. Trust me on this... It makes things easier down the road.

Same harness shown above installed:

IMG_0752.jpg


I like buying stuff from these guys:

Rhode Island Wiring Service Inc.

They are geared towards older cars, but they have a lot of the stuff you will need.
 
Without knowing the condition of the car in general, replacing all the wiring is akin to replacing all the plumbing in your house without knowing of any particular problem. If it looks like the truck, I'd say go for it.

If it looks like the gold sedan, I'd say you're crazy.

IMG_20161011_144611.jpg


IMG_20161217_121855.jpg
 
Being one of the guys that had a car *almost* burn up, I know for certain that the condition of the harness was not the issue. I had popped the fuseable link two days before I was supposed to drive the car down to winter storage and there was a storm on the way so I took it to a garage. The mechanic neglected to tell me that he simply bypassed the link so that when the problem occurred again on the highway, it just burned up through the harness.

The actual problem that blew the link was in the charging system. Had that been addressed properly, I'm sure I'd never have had a fire in that car. Live and learn.

However, if you're ripping into a resto, indeed, check everything through and clean and/or replace as necessary. It'll save you time and give you trust in the condition of the electrical system that you wouldn't otherwise have even with a new set up.
 
If you plan on removing the harness, then do it carefully, lots of photos before. Lay it out and examine the terminal ends and repair as needed.
Pay close attention to high amperage areas. If it is a Mopar you working on there are some documented up grades that can be performed. Be specific and ask questions in the appropriate threads. Someone here can get you through any question you may have.
 
Thanks for all of the responses. I already have the harness out for the front half of the car from when I changed out the stub frame and there are a bunch of "Patches" already (Some one else) made in it. So the front one I think should be rebuilt. I didn't know if people were able to order replacement ones. My dad was able to get one for his 50 plymouth front to back so I didn't know if we could/should do the same. But for now inspect and replace as needed.
 
I have been constructing my own harnesses using the original as a template but increasing the awg of the wire where I could .
I was surprised to find that even in the 60's Mother Mopar was using 16 & 18awg wiring.

In some cases the wiring insulation is hard and brittle which could lead to cracking

I still have to require the under the dash and add the headlight relay system then I'm done with my Polara

I found the factory metal connectors on DellCity.com at a really good price and they sell the crimpers too
 
My car restoration project planner is my checking account balance.
YO TAMBIEN! Given an unlimited budget, I'd be rebuilding from ground up. My OTHER major constraint is: "Does this make the car stop safely, or go safely?"

I've been doing wiring on basis of how much current they carry and their condition. My '66 Newport is simple, which is exactly why I stick with pre-1972 cars in general, and pre-1967 out here in Toostoned, AZ.

Next WIRING issue: Turn signals

What Big John advises is how they did wiring harnesses in mil-aero, and at the University too when I attended. If I had time and resources, I would too. Having to drive my work usually within hours of doing it, I have to get it right in situ. Thus far, Deo gratias, I have. Helps having the FSM.
 
Aug29,2007 092.jpg
I guess I will be the odd man out here.
First, what are your plans for the car? Upgrades? Stereo? USB chargers? Lighting upgrades? Dash/instrument upgrades? Electric fans? Electronic ignition? Or keep it all stock?
Upgrades take juice, more juice in those little 40 year old wiring harnesses, imho, is asking for trouble.

In my Duster, I think every wire under the hood and dash had been cut and spliced into.
I bought a kit from Ron Francis Wiring and am real happy with it. Peace of mind that when I crank it up and go I do not have to give any thought at all about the wiring harness.
As stated above, just my humble opinion.
C
 
I build my harnesses myself. But granted I work at Painless it makes it a little easier to do. Eventually I will end up redoing the entire car and will use one of our harnesses on the Fury.
 
View attachment 108995 I guess I will be the odd man out here.
First, what are your plans for the car? Upgrades? Stereo? USB chargers? Lighting upgrades? Dash/instrument upgrades? Electric fans? Electronic ignition? Or keep it all stock?
Upgrades take juice, more juice in those little 40 year old wiring harnesses, imho, is asking for trouble.

In my Duster, I think every wire under the hood and dash had been cut and spliced into.
I bought a kit from Ron Francis Wiring and am real happy with it. Peace of mind that when I crank it up and go I do not have to give any thought at all about the wiring harness.
As stated above, just my humble opinion.
C

I sure do hope that's a "before" photo, because it's exactly what I picture when I think about people re-wiring their cars.
 
Thanks for all of the suggestions. I think what my wife and I decided(She said she would "assist") is that were going to redo the headlight harness and engine harness the way Big_John suggested. I'll post pictures of my project during the process. I should be grabbing the parts this weekend from Michigan and taking them with me to New York. If these go well I'll move towards the dash harness. It will be coming out anyways this summer while it is getting painted. Should I replace the wire with Identical wire sizes or slightly larger? Thanks for all of the responses.
 
Thanks for all of the suggestions..... Should I replace the wire with Identical wire sizes or slightly larger? Thanks for all of the responses.
One gauge thicker...
If OE was #18g go to #16 or #14
If #16 go to #14
 
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