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DIY wire harness questions.

2K views 11 replies 8 participants last post by  Rip VW 
#1 ·
I'm hoping that this forum will help me come back up to speed after over 30 years. I have 3 different projects: a 1970 Camaro, a Factory Five "roadster", and a Chump race car (with my sons). I belong to several specific boards for each but this site looks like a great source of general information on all things in the hot rodding world. I'm just starting the wiring on the Factory Five and I'm looking for help with the wiring. I've bought a couple of books and done some wiring projects on the Camaro (new halogen lights with relays) but I'd like to find a general layout (not a schematic) for the cobra so I can build my own harness rather than spend $$$$ on a harness that has lots circuits I don't need and some that I will have to add.

I live in a car town with lots of local resources that cater to NASCAR but sometimes they're too specialized.

Rustle
 
#2 ·
You'll find that it is way easier and simpler to order a component-specific wiring harness from one of the many suppliers of custom harnesses. I like Painless, but there are many different ones who will make a custom harness for you. Just call 'em up and tell 'em you want a 21 circuit harness for a glass car....
Search Results | Painless Performance

The option, making up a harness yourself, leaves you hanging out in the breeze as far as quality components. Do you know who made the wire? Is it make of Chinesium? Where were the other components made? Do you know if that wire that's advertised as 14 gauge is really 14 gauge? A professionally constructed harness made of quality components will be the cheapest part you ever buy for your car. Trust me, been there, done that many times.
 
#3 ·
I have a guy here locally that makes harnesses, builds his own fans etc. he is about 1/2 of what the name brand harnesses cost. I just installed one in a buddy's 46 truck over the summer and he has use them in his other builds as well. I think he would build to whatever you want and ship it not sure i could get his number if your interested. We be in So. IL.
 
#4 ·
Thanks to you both

I am interested in talking to someone who could build a completely custom harness, so please send info.

I reviewed the "reviews" of the various harness suppliers and it seems like they all get good reviews. I've looked at multiple sites (Painless being one) and have put a query in to American Autowire. I have some experience having just upgraded the front section of the Camaro harness. I used Waytech for most supplies and built the PDM's using the Littlefuse modular system and the Delphi 280 series components. What that effort taught me, however, is that a full custom harness for the Cobra would probably take me way too long to build from scratch.

My dilemma is that a significant rebuild of a standard kit may take me as long as scratch building a harness since I have what I think are some rather unique requirements. So, I've officially reached the "analysis paralysis" state :confused:

All ideas and comments welcome.
 
#5 ·
Info

Russell Jones
email: russelljones48 at gmail dot com

harness is for a Mark IV Factory Five cobra with a Ford Coyote motor and Tremec T600 5spd.

Headlights and other lighting converted to LED
Electric fan(s)
50 psi HV fuel pump
OBDII based instrumentation via tablet and cell phone
Dash mounted conventional tach.
no heater, no wipers, no radio
might add seat heaters/warmers

Would like to consider splitting the harness front to rear with 2 fuse box/PDM's
 
#7 ·
I have made a few.

Start off wiring your 3 wire GM alternatior like this.



The goal here is to have a Junction point. This junction point is what you will run everything off of. I use these;

Catalog

You mount them in high load areas. You want one on the firewall for on at all times power, One on the firewall for key on power, and one on the core support to run your fans and headlights.

Then there is this;

http://diyford.com/build-cobra-kit-car-electrical-system-guide/

The book is something you want.
 
#8 ·
IMO... if you don't already have a junction point, why put one in..... come off the starter lug straight into where ever you need it or in my case ..... I like to run a resettable 70 amp circuit breaker straight from the pos post on the battery, from the other side of the C/B I run everything, fuse block, alt charge wire, fan feed ..... except for the starter and it gets a direct connection to the pos post.

Each time you add a connection, you add potential fail points and resistance.

Just my opinion....
 
#12 ·
I picked up a Harness just last week. I got it on Flea Bay. $111.00 with free shipping. The outfit that built the Harness is Called "Keep it clean". The Harness I bought was the KIC Pro 15.

So far I have laid it out on the floor and examined all the wires and connectors and the quality of work seems good. There are a couple of connectors to pick up and the pins too so far all I had to buy was a light switch connector and the Packard 56 terminals.

All of the wires are identified by both color and circuit function, the circuit name is printed on each wire the length of it. The harness is broken out into clusters like Front, rear, Dash, Column, etc. it is zip tied in places to hold the basic routing. The documentation is by download and has the wire list locations and any other instruction.

The only thing I did not see was the spec on wire insulation. I don't think it has the 103 or whatever spec that is used in today's modern cars. It looks like good ol copper stranded wire with a good strand count.

I have the harness splayed out in my living room and I am adding a couple of extra wires now before I wrap the harness and get it ready to install.

So far, I am impressed with the build quality, the fuse block quality and assembly quality. There seems to be plenty of wire to customize as you need and the front headlight wires are long enough to reach out front and tap the car in front on you.

Yeah if I was building something else than my coupe I would have bought two. :cool::thumbup::thumbup::thumbup:
 
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