Best resource for learning automotive wiring?

[Afdent11]

My kit hasn’t arrived yet, but I’ve been pouring over the forums trying to learn as much as possible. But no matter how many times I re-read most of the wiring posts, I’m still lost. I’ve tried to watch YouTube videos but they’re mostly too vague or simple.

So my question is, does anyone have a good resource they used to really get a grasp of all of the wiring situations you encounter on a build? Especially if you’re adding a little bit of basic customization? It’s just not clicking.

Thank you!

[MSumners]

Not all inclusive but when I was doing my Roadster i ordered the free ron francis catalog online and in the back there are a bunch of pages with tips. I found a lot of them very useful. Basics along the way I would just say have a build thread and ask here too. I'm not confident enough to answer most electrical questions but a lot of people here are.

[Afdent11]

Awesome! Just found their catalog and downloaded it from their website. Looks like about 20 pages of tips and frequently asked questions with good info. Thank you!

I’ll take all the resources I can get if anyone has others. Thanks!

[tnt_motorsports]

I have gotten help from members on here. I use this site for reference. I belongs to forum member weendoggy

https://www.weendoggy.com/wiring.htm#diagrams

[edwardb]

If you're that uncomfortable, I think it would be easy to get lost in a detailed book on the subject. The Ron Francis harness that comes with Factory Five kits is actually very basic. Much simpler than what's in production cars. Especially now. If you haven't already, I'd get hold of the Ron Francis Chassis Wiring Harness manual that comes with the kit. I think it's available via download. Lots of text with pictures but focus on the wiring diagram in the center. Seems complicated at first but if you study you should find it's actually very logical. Don't be intimidated by the various build threads (including mine...) where we dissect and modify the harness. It can successfully be used out of the box. Adding a couple circuits isn't hard but get the basic understanding first. Good luck. We're here to help.

[PMD24]

First and most important... you underestimate your capability to get this. Seems like many of us do that. I did. I went into this with no knowledge of automotive wiring and it was the one area of the build that I had the most concern about. I'm now just wrapping it up having removed wiring, shortened wiring, added circuits, changed the EFI harness, etc. I started by looking at one circuit at a time and tracing it out on the wiring schematics (in the manual that edwardb mentions above).

If you have a grasp of the simple circuits you mention from You Tube, you are 90% there. The RF harness (except for the circuits with relays) is just several of those simple circuits.

Note that in a car many of the circuits have the switching device on the ground side.

Pick a simple circuit to start off, like the horn. If you can't sort it out, ask here. You'll then be off and running.

Pat

[PNWTim]

Watson's StreetWorks also sells a little manual that breaks down each component or sector of a car, meant for street rods but aligns well with what we do, and is very simple. I picked one up just to see what it was like. Doesn't go too far down any rabbit holes and is pretty easy reading:

https://watsons-streetworks.com/product/basic-auto-electricity-book/

[Mike.Bray]

Most important thing in these automotive circuits is grounding. Ground, ground, and ground. And there won't always be a ground wire, like a temp sensor might ground through the mechanical connection to the engine which is grounded to the frame which is grounded to the battery. If you imagine a simple circuit like a light for example, you will have positive 12V from somewhere, probably the fuse box, and that wire goes to a switch to control whether it passes through or not. From the switch it goes to one side of the light and the other side is always grounded. Complete the circuit to the light and it is energized. Remove either the positive 12V or the ground and the light is no longer energized. That's the most basic circuit.

Now, printout the wiring diagram, preferable on large format, and start studying it a section at a time. I promise your light will turn on at some pint, probably pretty quickly. The RF diagram for these cars is pretty simple, just follow the wires.

Relays. these can be confusing but shouldn't be. Think of something like the fuel pump with an electric motor that pulls more than a few amps (power). To switch this motor on with a manual switch you would need a big heavy duty switch to handle the large electrical current it pulls. A relay is a simple device that uses a switched 12V circuit to energize a coil which then causes a large set of contacts to close. The coil pulls very little current so a small switch can be used to energize it. The contacts are larger and heavier duty so they can handle the current (power) requirements of the pump motor. As was mentioned earlier, some relays break the negative side of the coil connections instead what would seem logical in breaking the positive side. Doesn't matter, if either the positive or negative side is broken the coil will not be energized.

Hope this helps some. You got this.

And one last thing, engines run on fuel while motors run on electricity:)

[Afdent11]

Thank you guys so much for the responses, resources and reassurance! Even just your quick explanations in your posts made a few things click better. I’m excited to get going on this! Thanks!!

[Blitzboy54]

Like what Paul said, the wiring in these cars is really simple compared to a modern car. It's a lot more like a motorcycle (very basic), some things to keep in mind.

Everything is 12v DC (outside of the coil and spark plugs). I assume your buying an engine so anything you wire will be 12v DC.

Grounds are super important, easy to create and you cannot have too many of them.

I don't know if this helps but electrical circuits are not all that different from plumbing. Electricity "flows" just like water. It makes it's way to the drain. We call the "flow" current and it "drains" to ground. A switch is no different than a valve. There is potential energy on one side but it's not realized until it's allowed to pass to ground. The terminolgy is opposite however. You open a valve to allow water to flow. You close a switch to allow electricity to flow.

If you are building a "stock" roadster and not adding anything extra all you really have to do is follow the instructions. If you get stuck TAKE PICTURES, start a thread and ask the forum. Every chance someone here can help.

[OSU Cowboy]

Important electrical tip: Once the smoke comes out, it's hard to put it back in.

[JJK]

Just for some additional encouragement, having a mechanical engineering background, I was most hesitant about the electrical wiring for my build. I was never that great at counting the electrons. As it turns out, I found the wiring to be some of the most fun aspects of the project, perhaps because it offered the most opportunity to learn new things.
Some tips from my perspective: get a soldering iron and learn how to properly solder wires together, I used sealed heat shrink on top of all my soldered joints, when not soldered directly I used waterproof male/female plugs with pigtails on many parts of the build where I wanted the ability to unplug something in the future as opposed to cut and splice wires for maintenance (used 2 and 3 wire predominantly, depending on the application), I needed direct connections to the battery for a few things so used battery terminal clamp connectors for more versatility, I used a lot of split wire loom and cable clamps to keep wiring tidy, do not use wire nuts anywhere (this is a car not a house), I recommend against the butt or blade splice connectors that come with the kit in favor of soldered connections.

[CW_MI]

I've often found some decent articles and blog posts here. Toggle the search to "tech articles"

https://www.hpacademy.com/search/results/?q=wiring

[Bob Cowan]

Red = Positive. Black = Negative. There, you're done. ;)

[rich grsc]

Yep Bob, that's about it. :cool:

[Super Dave]

The best place are forums like this one and YouTube - Just keep watching videos, eventually it will make sense

Also I would recommend to use uninsulated wire connectors and adhesive lined heat shrink tubing, You can do a better crimp with the uninsulated connectors.
Use good quality connectors and tools

[TTimmy]

I have found the Painless Performance wiring manual to be pretty informative, in generic terms, regarding automotive wiring. That said, I would recommend you stick with the RF harness so you have the benefit of forum/community support. But I would recommend looking through this manual: https://painlessperformance.com/wp-content/uploads/2024/02/90626.pdf


Painless also has some videos: https://painlessperformance.com/category/videos/

[Afdent11]

Again, thank you guys so much! So much good advice and helpful explanations. I’m feeling better about taking it on :)

[M22_COBRA]

My old shop teacher explained it this way...
"You can hold THIS, You can hold THAT, but don't hold THOSE."

As a helpful tip in this arena as I was as unsure as you were starting on wiring. My advice...Go get a circuit tester that allows you to see if you are on power / ground / have no signal / or you can apply power and test your stuff BEFORE you install it. I got mine off the amazon for $20. Helped me understand / confirm where the power was going, and that my stuff wasn't broken before I installed it.

[Papa]

Lesson #1

To start to understand electrical wiring, you need to grasp the concept of a circuit. A circuit is, in very basic terms, a loop. Starting at the battery, current flows out from the positive post and in through the negative post. Electrical components are part of the circuit. They have a positive and a negative and will only work when the circuit is complete, meaning the flow of current leaves the battery and flows into the component and then back to the battery.

Now that we have a circuit with a component, we need a way to control the component (turn it on and off). We do this with a switch. A switch is a device that connects (closes) or disconnects (opens) the circuit. When it's closed, current can flow and when it's open, current can't flow. A switch can be on either side of the circuit (positive or negative). It does the exact same thing regardless of which side of the circuit it is on, opens or closes the circuit.

https://thefactoryfiveforum.com/attachment.php?attachmentid=227701&d=1775157612