For a simple diagram, I have been using one from an old Peterson Book called, Basic Ignition Systems, but I have copied your block diagram because it will make it easier for me to explain the system to other people. Bob
Where's your taillights? Horn? Where's the ignition switch go? Dimmer switch for the headlights? You have a 50A circuit breaker for the fuse panel (which given the loads shown is hugely oversized), where's the rest of the fuses?
There are so many post's because it's not easy for many. And it certainly isn't as easy as your diagram suggest's. It isn't just connect the dot's and all points make contact as they should.
You do know that there's virtually no automotive keyed switch that can safely and reliably carry a 50A load? The biggest I've seen (with a legitimate rating) is only good for 24A. I hate seeing stuff like this posted because with wiring, the devil really is in the details. You might want to read this... https://www.jalopyjournal.com/forum/threads/wiring-101.843579/ ... and re-think your design. And a functioning horn is required pretty much everywhere.
Model A's didn't come with electronic ignition and tach so those blow your simple diagram theory out of the window. It should show complete ignition and starting circuits, head and tail/stop lamps, horn and wipers. Depending on year model, turn signals and high beams. This would at least meet basic requirements to pass laws in most states. Connecting dots is not a proper wiring diagram... If someone can't read a simple wiring diagram, they sure shouldn't be wiring a car. Sent from my Moto G Play using The H.A.M.B. mobile app
There's always guys looking for a 'magic bullet' for wiring design. Sure, it your car is a '40s or older, very bare bones, and you don't add any newer safety items like turn signals or have a radio, heater with a fan or electric wipers (or any other electric devices), you can get away with a pretty basic harness. Even so, there's still some skull sweat involved and you can have a fair amount of variation in the design depending on all the components used. The OEMs moved away from these style harnesses because of safety and reliability issues. Two, guys will try to start with a 'basic' design and then add stuff to it. Several issues with this; one, you'll probably duplicate wires that don't need it. Two, as the design gets more and more 'layered', the diagrams get increasingly harder to read. I hate 'total car' diagrams for just this reason. You're far better off to design each 'system' separately (like the lighting diagram above, although I can see two issues with it, one major) and then integrate the systems together. Three, in spite of the fact that numerous aftermarket vendors will claim their harness is 'EZ' or 'Painless' to install (and I'm not calling out just those suppliers, they all do it), they're as guilty as the OEMs about skimping on wire size. Big difference is the OEMs have full engineering data on every component they use and how much they can get away with (and still get it wrong on occasion). They are also using all-new components; are you? The aftermarket furnishes 'generic' circuits that may or may not be correct for whatever you're connecting to it, and are equally guilty of skimping on wire sizes. Then they sell you relays to 'fix' their design flaws... further complicating the harness. Harness design isn't rocket science; while having extensive electrical knowledge is a plus, if you're willing to look for the right info (and granted, accurate automotive info isn't always easy to find), anybody can wire a car. Just don't expect it to be a quicky weekend job if you want it done right. Guys will spend hours, if not days perfecting brake, suspension, and fuel system design and then rush the wiring. There's easy-to-use voltage drop calculators available on the 'net, just using one of those would cure probably 80% of all harness issues.
Asking for a simple diagram is like asking how long is a piece of string. What are you running? 6v? 12v? Alternator? lights?radio? List everything you need to run, have a couple of spare circuits just in case, and you are about 1/4 way there. Knowing some real basic stuff (ohm's law, series/parallel circuits, how to use a multimeter) will really help.
What this all boils down to is that there are no short cuts to wiring a car so there can't be a shortcut to the schematic. You have to know what needs to be wired and draw it in. Mapping out where all of this wiring is going to go.... Whole nother can of worms. Sent from my Moto G Play using The H.A.M.B. mobile app
Over the years I have collected a lot of how to books and the wiring reference I always seem to go to is a thin little 66 page Orange book called "How to Wire Your Street Rod From Start to Finish". Written by Jack Sweeden and sold by all of the book companies. I'm pretty sure my copy came from Speedway and was around $5. The author breakes down all of the GM, Ford and MOPAR to their basic components and really explains how it all works. He covers both generator systems and alternators. Skip your next Starbucks Latte and invest in the book.
It appears that on pre-52 Ford cars didn't come with turn signals. My 41 Ford didn't come with turn signals. I added those on using a universal turn signal switch mounted to the column. I want to say that a lot of pre 50's cars did not have signals. My dad's 50 Chevy sedan doesn't have signals either. So from a stock wiring perspective, I like the simplicity of that wiring diagram.
In Texas... High beams and indicator lamp are not required on vehicles built prior to Jan 1,1948. Turn signals are required on 1960 and newer vehicles. Other states may different but as a general rule, these are when government regulations required them also. Also on the turn indicators... They must be self cancelling. Toggle switch won't pass. Sent from my Moto G Play using The H.A.M.B. mobile app
The problem with the above diagram is using separate turn bulbs in the rear in the same housing; when the brake lights are applied, you won't see the turn signals. My avatar was set up like that when I got it, and I got complaints about it.
Uh oh...it looks like the original poster is no longer with us...I was going to send him a PM and I am getting the 'ol "THE H.A.M.B. - ERROR" page.
Note his sigline in the OP. Probably for the best. People who drive 15mph down the highway when it's raining probably shouldn't be driving down the highway.
He wasn’t looking for advice.... he wanted you to agree with him. That’s what I like about this forum... somebody here seems to be an expert on anything you bring up. If everybody agrees with me, I didn’t learn anything, and I don’t agree with every post either. But everybody has the right to their opinions. And what pisses me off is, if you ask a question... at least LISTEN to the answer of the person you asked. Just my .02. Bones
I used to have a neighbor who would ask for automotive advice. He was also a notorious cheapskate; if the choice was cheap and wrong vs expensive and right, he'd try cheap first every time. Then when he had to re-do it, complain that the 'right' repair was expensive... Anyway, he usually had electrical questions and when I'd explain what was needed, he'd then argue with me. Finally I asked him one day that if he thought I was wrong, why even ask? His answer 'Well, you're pretty smart with this stuff'. So I ask him 'What do you know about this?'.. 'Well, not much' (closer to zero IMO). I told him if you come over and ask one more time and then argue with me, we're done. He quit asking... I was a licensed electrician/administrator at the time, had been an instructor in AC/DC theory, and have wired/serviced everything from motorcycles to industrial process lines.
Steve, I had almost the same situation with a friend of mine... I finally told him the same thing. Steve, we’ve had conversations before and I do consider you one of the experts here. Bones
People are funny... Like I've said, guys will spend all sorts of time working the mechanical aspect of their project yet many still think that 'electrical' is some sort of afterthought. But unlike mechanical, electrical won't always show if there's issues, at least until the smoke leaks out. I've seen terrible crap work trouble-free for years, and seen otherwise nice jobs with only one flaw go up in flames; you never know... But the degree of installation difficulty between a maybe-OK harness and one that's right is very little. And cost-wise there should be little difference; for most cars, no more than $100, it may even save you money if you don't need to go back and 'correct' issues. It's the pre-installation planning that takes time, and is the area where 'shortcuts' can have disastrous results.
I was lucky, for 33 1/2 years I had all the money and time I needed to do the job right, for the place I worked at. Starting with no formal training ,in 1979 , I did it my way( to quote Frank). That was before we had the internet and could share knowledge. I had a small group of knowledgeable friends that I could count on . But that was about it. I joined a group of “ technicians “ in California and was a amazed at how them were networking and learning from each other. I jumped at the chance years later, to be a Charter member of Oklahoma Emergency Technicians Association and we then helped neighboring states form their associations. After that the Southwest Conference was established. That along with the internet , helped with the sharing of information concerning everything that had to do with Fire trucks and Ambulances. If you think your Hotrod electrical system is complicated, look at a Fire Engine. Bones
Sorry no. I posted only to show OP that one just can not draw a single line from a given source then to given load without a full understanding of what's fully needed. That "example" was never meant to be interpreted as complete blue print to any one. OP is the one attempting to do so.
What a crybaby I was going to post here last night but thought better of it. But fuck - it it's Friday night now This guy never wired a car before, decides he's going to set everyone straight and teach with a simple wiring diagram?!? Then get bent out of shape because someone says "nope, that's not right." Last time he had melt down he was quit posting for a few months. Hope it's longer this time. Thank goodness it's gone and no innocent seekers will be harmed. "Cry baby" is a bit childish of a term but gosh does it fit. An Immature individual with cognitive distortions and lack of control over their emotions is technically more correct but "cry baby" has a better ring.
The Jalopy Journal
