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6/25/2022 12:15 PM  #1


Wiring harness question

Ok, so I’m working my way through my mustang and I’ve known for a while I’m going to need to tackle the wiring on my 66 mustang coupe as the wiring is brittle and when you strip any portion of
It it’s corroded with green mixed in with the copper. I haven’t really had any issues with it.. knock on wood.  I have it driving and running nice but I think I should really start looking at doing the wiring soon before I start seeing problems. I’m debating going with American auto wire or painless. Has anyone had any experience with these. Any input is appreciated.  Im going to be looking at adding some modern features like led headlights and electric fan maybe power windows and door locks.  Do these kits have the required circuits for that type of stuff?

 

6/25/2022 12:47 PM  #2


Re: Wiring harness question

I did the AAW kit. It has circuits for everything but you will need to upgrade to a 3G alt cause it is not compatible with a stand alone voltage regulator. Each wire is individually marked for function and are extra long. I would recommend putting the fuse box in a more accessible location other than the stock position
It has relays for head lights etc.
I have no experience with Painless other than what I have read that the AAW is better.
They have excellent after sale customer service.
Their kit has wiring feeds for power windows, remote door and trunk locks which I have, but I wanted those circuits relay operated which were not in the kit.
I also moved my battery to the trunk an hid most of the wiring in and out the engine bay.
I don’t have anything negative to say about the kit.
After doing all the wiring on my ex. airplane I was perfectly capable of sourcing the fuse box, wires, relays etc and saving some bucks but decided the AAW kit was a better route.

Last edited by Rudi (6/25/2022 1:03 PM)


Good work ain't cheap, Cheap work ain't good!   Simple Man
 

6/26/2022 4:39 AM  #3


Re: Wiring harness question

Something to think about- If you go with an OEM replacement harnesses like Alloy Metal Products (available from NPD) then your car will match the original wire diagrams and anyone with a FORD diagram can help. Once you change to an aftermarket harness you are on your own, or can only get help from the manufacturer or other users of that harness.
The newer fuse blocks are nice and often have added relays, but the documentation is usually in the form of a "branched highway" wire diagram, not a traditional "point to point" diagram. On a branched highway you see the wire enter the highway and have to look all over to see where it comes out- a real PITA.

 

6/26/2022 6:15 AM  #4


Re: Wiring harness question

I also used the AAW kit and agree with Rudi's comments and would use the AAW kit on another car without hesitation, but Mach1 raises a fair point.

I guess it depends on the plans for your car...if you car is going to remain stock or close to it in terms of electrical accessories, then it might be better to go with a factory style replacement harness like Alloy Metal Products for the reason Mach1 mentions (plus, a factory style replacement harness will be a lot faster to install),  but if you plan on adding things like power windows, power locks, heated seats, electric fuel pumps, electric fans, etc., AAW may be a better/easier option as all of those circuits are already provided for.

 

6/26/2022 7:29 AM  #5


Re: Wiring harness question

I purchased both the 1966 chassis and a 5.0 EFI harness for my 1966 mustang.  It was expensive but it was all there.  Take your time and just nibble at it.  I would worked a few hours on the evenings and half a Saturday till I go it all wired up.  Here's my advice:

1.) Think ahead to components you might want to add such as A/C, digital gauges, fog lights, premium audio, dome light, etc.
2.) Buy the premium wiring tape that the high end cars use.  It's almost like a felt and you can buy large rolls on Amazon.  DO NOT USE THAT CHEAP ELECTRICAL TAPE!  That stuff just turns in to a sticky mess eventually.
3.)  Invest in a good test.  One that both does continuity, and voltage check, and can power a component.  You'll save a lot of time when you can directly apply a 12v source to quickly troubleshoot if it's the component, switch, ground, or your wiring.    
4.)  All those old plastic clips and connectors will likely crack and break when taking them apart.  Plan on replacing them  60 year old plastic becomes very brittle.  
5.)  Learn to create proper grounds.  Can not stress this enough.  You must properly ground the entire system or you will be chasing issues forever.

 

6/26/2022 10:27 AM  #6


Re: Wiring harness question

I used the AAW and over all it's pretty good. A few issues; the wire diagram as Mach1 pointed out, a good schematic would be nice for future trouble shooting. I remember something about the fuse block being mounted where the AC unit goes. Keep in mind if you have an AC car. The relays for headlights are mounted in the cab. These are most effective when mounted near the headlights. Mostly minor issues.


If this forum can't fix it, it isn't broke.
 

6/26/2022 11:48 AM  #7


Re: Wiring harness question

Okay....I hope you guys are happy.  You shamed me into it.
Six years ago I built a complete new harness for the Heap.  Power Distribution Box under the hood with all EFI, Headlight, Horn, Accessory Circuit relays and fuses and a twenty circuit accessory fuse panel in the cabin.  I included everything I could think of that I might someday install in the car and I kept fairly good notes and drawings....Butt (TS&T), I never drew the wiring diagram so that I or someone else might be able to figure out what I did ten years later.
So you have shamed me into it.  I just went to the shop and got the folder with all the harness info and I'm at the computer and I'm working on it.    Jean has the "Bug" so we are hunkered down.  Seems like a good time to do this.
 


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

6/26/2022 6:08 PM  #8


Re: Wiring harness question

Yeah butt...........
BulletBob.......remember the really cool time we ALL at MS old house in Carrollton . In the driveway....9:00 at night....THREE of us under the dash with a stink'in penlight......Glenn  operating the power to & from the battery  (ya-had-to-be-there)...smoke rolling out from under the dash....butt no lights!!
  Around midnight most everybody had left except you and Dumbernhell Don Sellars and Corky .
  MS pulled it into his garage and pulled the steering wheel.
"Horn thingy was grounding out on the steering column...it coulda burnt down the whole car" (one of FoMoCo's 'better ideas' I guess!)
We "borrowed" one from Ramses's Mustang and.........end of issue!!
You just can't have THAT kinda fun with a fancy 'new' harness!!! J/K

6sally6

I was starting to get a might worried about getting back to SC the next day!....I DID and that was history


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

6/27/2022 7:03 AM  #9


Re: Wiring harness question

I do recall that evening well-spent.  Our first Bash, met a bunch of really good folks and figured out my #460 wire/horn relay mod, which I think you now have.  All because Ford cheaped out and did not install a horn relay.  I remember the circuit breaker in the headlight switch kept trippinjg/resetting so, of course, the lights did too. 

Last edited by Bullet Bob (6/27/2022 7:03 AM)


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

6/27/2022 7:37 AM  #10


Re: Wiring harness question

Since you have a 66, this link may be of interest. Someone mentioned a schematic above, but most people don't know what a real schematic is, because FORD only released wire diagrams. Diagrams have the wire colors, numbers, plugs and where the splices are located. You need them, but it is often difficult to see the entire circuit and how it works. Schematics simplify the circuit so you can see it at a glance. In my opinion you need both the diagram and the schematic. I made one for my 69, and since 66 had the most cars, I just finished one for it. I backward engineered from an Osborn wire diagram. You can find the diagram free on Average Joe Restorations, but the schematic is in the link below.
Note: These drawings were done in an 18 year old CAD program. The only reasonable way for people to view high resolution files is if they are saved as a pdf. However, the pdf in this ancient software can only output in portrait mode. Since most of the drawings are in landscape mode, I had to rotate them 90° prior to saving as a pdf. Just print the page(s) wanted and you will have a full landscape A-size pdf. Sorry for the inconvenience. The Schematics also have a table of contents so you can find the page that holds your area of interest. There are several other documents that may be of interest in the folder- feel free to download whatever you please:
https://drive.google.com/drive/folders/10FqYlsGT1XXr8B5TCF9WAASkU4vdPtuJ?usp=sharing

 

 

6/27/2022 9:47 AM  #11


Re: Wiring harness question

Thanks Terry for your time and effort. You plan on making it to the bash in Vandalia Illinois this year? It's only an 8-hour drive for you. Sure would be nice to meet you.


Bob. 69 Mach 1, 393W, SMOD Toploader, Armstrong  steering, factory AC.
 

6/27/2022 10:05 AM  #12


Re: Wiring harness question

I'd like to meet you too Bob, but I don't think I can make it this year 

 

6/27/2022 11:38 AM  #13


Re: Wiring harness question

I bought a Painless kit then stored it for 4-5 years before I installed it. It wasn't painless by any means, but that could be more on me for the changes I made. It did go together well.
Cons
The headlight and ignition switch they supplied were junk. 
I had to make every end point termination, but I guess that would be the case with anything other than a factory replacement. 
I had to add relays for the head lights.
I would have been nice if painless would have included connectors in all places that Ford had them, like the firewall plugs and front running lights. I soldiered and heat shrinked the connections I made.
I didn't like the 70A blade fuse they sent for a main. Used Bullet Bob's reference guide for wiring to purchase better stuff. 

Pros
The wire was long enough to route any way I saw fit.
The wire colors matched what Ford used on a 67 model, which I thought was good.
Mine came with a relay for the horn built in. 
There was (1) 20 amp circuit that I could use for what ever. Can't remember what I used it for.... thinking I saved it for fog lights. The power window kit I bought needed more than 20 amps if I recall. 
I liked that it was new wire and better insulation than Ford had available. 
The instruction manual was very good. If you go with Painless, make sure to keep whatever instruction manual they send. When they make updates to a harness, the most recent version of the manual is all that remains on the website.
The customer support was good as well. I have a factory tach car and the instrument cluster wiring they offer does not have provisions for the tach and idiot lights. I drew up something that I thought would work and walked through it with them and they agreed that I was in good shape. 
Painless offers a sleeving material to cover wire. It works great, but can be sourced a lot cheaper from other places. 

I added a 3G alternator, dura-spark ignition, power windows, power seat, USB charging port and had to figure all of those out as well. I still had to add an auxiliary fuse block to get feeds for power seat, power windows, and a USB charging port. Now I need to go back and change some things so part of the circuits I added will be on off with the key. 

Whichever way you go, think it through, draw it out, place items where you think it will work. Do all that you can to have a sound game plan before starting. Once you start, changes can be more time consuming the harness install itself. 
 


John  -- 67 Mustang Coupe 390 5 speed
 

6/29/2022 7:55 AM  #14


Re: Wiring harness question

Wow thank you everyone so much for your replies and thank you so so much Mach1driver. I greatly appreciate you sharing those schematic’s. That is going to be so helpful.  After reading all the comments and looking at the websites for American auto wire and for painless. I looked into the stock harness being sold from npd. And I found a Scott drake one which is a main under dash one. But it has a modern 12 circuit atc fuse block and relays. It also has correct connectors and color coded wires l. It also has a spare hot and keyed terminals on the fuse block. It looks like it may be a little more expensive than doing a painless or aaw one as the other harnesses I’d have to buy for it. But this would I think maybe let me customize it more and with possibly less work than doing one of the other ones.

Has anyone seen one of these Scott drake ones.

     Thread Starter
 

6/29/2022 12:10 PM  #15


Re: Wiring harness question

Just my opinion on this, but unless you can figure out who makes the Scott Drake harness, I would stay away from it. I have started actively trying to avoid Scott Drake products because some much of it is crap these days (with some exceptions) out of the box. I can't tell you how many items I've had to buy something twice because the first one was Scott Drake and it broke/fell apart/didn't fit, etc. I'd be very leery of the quality of a Scott Drake harness and would be reluctant to use one, especially given how involved it is to remove/replace it if you have to.


But maybe someone who has used it can weigh in with their actual experience.

 

Board footera


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