View Full Version : Learning Automotive Electrical Systems...

04-06-03, 04:52 PM
As many of you are aware, I am in the process of completely redoing my dash.


I will be changing the digital cluster to analog gauges and eliminating the associated driver information panel, along with many of the factory-installed options, such as the UDT/VATS, the chime that alerts you if a door is open, and the other indicator lights in that panel (SES, "Hatch Ajar", ABS check, etc.). The radio will also not be installed, at least initially.

I will retain the air conditioning, and because the windows aren't equipped with handles, I will have to retain the electrical to the doors and hatch. However, I will be stripping the harness of all other excess wiring. In other words, I'm starting fresh here.

Now, being a novice (to say the least!) at electrical wiring and building harnesses, I NEED advice.

After the work I have already started with the harnesses, two things come immediately to mind: How do I: Start with a circuit once it has been determined that it will be used? Do I start at the fuse block or do I start at the other end of the circuit?

How does one go about building a board upon which to lay out the wiring harness? (for ease of bundling)


Any and all advice will be most gratefully appreciated. :upthumbs

04-07-03, 06:26 PM
Does anyone have a book title they would recommend for learning tricks of the trade, or "How To..." books on building harnesses? :confused

_ken ;help

Tom Bryant
04-08-03, 11:52 AM

I know that I have seen automotive wiring books before. Have you checked Classic Motorbooks?


04-08-03, 12:09 PM
Unless your bound and determined to build it yourself there is an easier way. When I did my street rod I had a place called painless wiring build me a harness. I just gave them a basic drawing of what went where and what gages and so forth I was going to use. They put together the harness ( all wires marked where they go) and the fuse panel assembly. I don't remember the cost but it was alot less ( in terms of Manhours and wiring costs) than if I had built it myself. You could call a couple of these companies like painless or Ron Francis and see what it would cost. It was a piece of cake to do it this way and I didn't have to worry if I had something wired wrong ( read short and subsequent fire). Well whatever you decide it would make sense to me to start with the fuse panel placement and wire to and from there. Good Luck.


04-08-03, 09:01 PM
Thanks Randy. I spent some time last night at the Ron Francis site, as well as AutoRewire.com and a few others, including Painless, but I didn't get the impression that my vehicle's needs was something any of them covered. You're telling me that if I provide a crude diagram of what I need they can build it for me? Do you think any of 'em would understand that what I want is to strip the factory harness of all the wiring that I will not be utilizing?

I understand about working from the fuse block outwards when building the harness, and I certainly understand that it would be nice, not to mention the easiest way, to have someone build a harness for me. Whoever that someone is though, they will have to understand the C4 Corvettes in addition to knowing wiring harnesses.

I see cars at shows and at the race tracks, I see cars in magazines, I see cars here at the :CAC, all having some sort of modified dash and looking professionally done. Why is it all of the people that I do get the names of all live on the east side of the country, with a handful in the mid-west, while I cannot find a single person here in SoCal that can (or will) recommend an automotive electrician (customizer/racer/etc.) to help me out here.

Nothing ever seems to come easy anymore. :hb

_ken :w

04-09-03, 05:15 AM
I would just give them a call. The Street machine I built was a 54 Chevy. Basically a drag car but steetable ( kinda) and I completely modified the dash and all the electrical wiring. I sent Painless a sketch of where everything went, what gages I was to use, and they took it from there. Sorry everybody lives on the wrong coast for you. These wiring harness guys do street rod, drag car, and other harnesses so I would think they should be able to build one for you. At what cost?? who knows. On one other car I re-wired complete, I worked the primary wiring first to the fuse block then to the accessory it operates and then did the lights, horn, dash, wiring last but that was just the way I did it. Used the original wiring diagram and made a copy and then drew in the changes for the new things added that had to be wired. If you do this you will find there are alot of wires you have eliminated by removing the accessory and that leg can be used for another circuit. Why are you completely rewiring the car? Was the wiring that bad? I know you are modifying the dash and all but is the original harnes for the light circuit and the engine management circuit bad? If not you could re-use or modify and just add in the harness for the dash with the new fuse block assy. Well, you definitely have your work cut out for you.


04-09-03, 08:12 PM
Originally posted by vette-dude
... you definitely have your work cut out for you.

You said a mouthful there boy! :eyerole

I think that unless I can get a real good deal on having someone do it for me, I'm committed to do it myself. It's too late to change my mind and stop now. :eek

The method used when you did the wiring in the "other car" sounds like a plan to follow. I don't know how else to go about it. ;shrug

I eliminated another accessory wiring concern today by removing my air conditioning. I never use it anyway. ;)

_ken :w

Oh, by the way, the wiring was butchered up pretty bad; that is what prompted me to try and straighten the mess out in the first place. :D

04-09-03, 10:40 PM
Hey Randy, I noticed this in the FAQs section of the Painless site:
*Do we custom build harnesses? Not on a single-harness basis. We have a variety of universal harnesses in stock that can fit almost anything. Call us and we can tell you which one we recommend. If you were to need a quantity of harnesses, you can contact us to submit your sample design and we can do a quotation for you.

_ken :cry