50 Chevy with electric wipers, radio converted original, 200amp alt, and vintage air Gen V ac. Battery is in back. Has original wiring now and everything works fine ac is one year old and is wired per VA with hot off ignition on terminal, all other ac wires are off battery. So how many circuits do I need? Can’t see the need for 18 or more
They all have more circuits than you need. Just beware that you might have a lot of extra wires, if you get a universal harness that is made for adding lots of stuff you don't have. good luck
What are you trying to accomplish? Keep in mind that wiring methods changed starting in the early '60s and most aftermarket harness kits reflect those changes, leading to compatibility issues if partially rewiring an early car. One thing is a new harness will have smaller wire than your existing 6V system, possibly introducing excessive voltage drop on most circuits unless you purchase a '6V' harness. You may want to read this... https://www.jalopyjournal.com/forum/threads/wiring-101.843579/ ... before making any decision.
Sorry i didn't say it already 12 volts. I will probably have to pull the AC to change expansion valve. If I do thought it would be a good time to put in new wiring and a Classic Instruments cluster this is the harness I'm looking at 12-circuit-universal-wiring-harness
On my 54 sedan, I used a 12 circuit similar to the one in the link provided. There was extra wiring that wasn't necessary, but I just coiled it up under the dash. Always better to have more room to expand in the future.
Put a barrier strip near the panel and wire the extra wires to 1 side of it. In the future, if a circuit is added, just link to one that has the proper size fuse in the panel. Gary
Long running thread. https://www.jalopyjournal.com/forum/threads/wiring-101.843579/ I'd suggest that you layout exactly what you have and want. Where the fuse block will go, then each part that gets power. Have it on paper in front of you. Then call the companies you hope to use, preferably more than 1 or 2. Get their input and compare what they say you need as far as wire, protection, circuit numbers, and how well the tech line can handle any questions. Are you planning on reusing old switches, bulb sockets and other OE components? In other words, spend a bit of time getting informed and then making the decision. You may get a consensus here on the title question, but now is the time to learn, before you buy.
^^^^ exactly what Rod said. Adding to that, gauges- ammeter or volts? Cloth wiring or PVC? Once you have all of the info, draw it out on paper and contact the wiring companies. 12 circuits should do it. Do some research- some kits label their wires about every 6 inches, some don't. How is the fuse block made, type of fuses, and are the fuses labeled? Are relays built into the fuse block? I have used Ron Francis, Rebel, Painless, DIY, and others. Recently bought a cloth covered Speedway Motors 12 Circuit to use in one of my Buicks.
Keep in mind that an advertised 12 or 18 circuits counts everything you didn't include, lights, signals, horn, gauges, etc. Make a list of what you need and go through the instruction manual of the kit you're looking at to see if it's big enough. You'll be surprised how fast it all adds up. Look at the description of one of the smaller painless kits for all that they count as circuits. https://share.google/UmsTan6nPyDCptios
I've used 2 Rebel 9+3 kits. One in my '39 p/u and one in my '54 Ranch Wagon. The 9+3 in the '39 was over kill but I got a deal on it at the Big 3 swap meet years ago. The 9+3 for the '54 worked fine. No power windows/locks but a/c. The tech support was great but not sure if anything has changed since Rebel sold. JMO
Here is the 1950 car and truck WD. https://i.pinimg.com/736x/11/f5/85/11f585f4b762ca604714ff43684ca41b.jpg This shows all the OE components. Add any additions, change anything that has been changed. The wiring colors and junctions at the front lights aren't required, but the general layout and components are what you need to make a new 'map'.
Wiring kits from China have really come down in price so more circuits aren't much of an issue. When you have less than what you need, it is a lot of trouble to add more.
A while back I bought a really cheap wiring kit for an off topic car, and ended up not using it because it was useless. No switched fuses...they were all on one bus. So just be careful that what you buy will do what you need.
I bought a Rebel 9+3 kit before they changed ownership, based on their positive reputation. Cory replaced Jeremy and has been excellent help when I have had a question. I've complicated things by using a Duraspark II ignition, a more compact, later model starter with a built-in solenoid and dividing my dash into two areas: the usual Model A dash centered in the back of the gas tank (fuel gauge, voltmeter, oil pressure gauge, speedometer and horn button where the dash light was); and the overhead console (composed of water temperature, tachometer, transmission temperature, ignition and light switches, hazard switch and indicator lights for left turn, right turn and high beam). I figured the only way I could understand how to wire it was to think like an electron and mentally zip through the wires doing what each circuit needed to do. I've still got some lights to wire up and the turn signal switch but the rest of the system checks out so far.
I try for four more circuits than what I am installing, or whatever is the next higher available increment available if +4 is not an option. For the unused ones, I run them out to a terminal block, and attach them, but leave the fuses out. That way, if changes need to be made in the future, they are a screw and fuse away.
My suggestion is to buy a "Name" harness and get one that already has any wiring you may want to add in the future. Second, get a copy of Ron Francis's catalog. It is a wealth of information done in a simple manner for electrically challenged individuals like myself. This doesn't mean that you have to buy their harness, but it has a lot of "Tips" with excellent explanations. They do make good harnesses and so does Painless Wiring. There are other good harnesses available as well. I would not skimp on price when getting a harness, but you may not need one with provisions for components you will never need. Just remember that having some extra wires available may provide you the ability to add something else later .......even if that circuit wasn't labeled for that kind of an item. Here is an exerpt from the RF catalog.
My avatar has everything you do Except radio and air on 12 circuits. I could have installed the radio; no room in the dash.
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