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Step-by-Step Basic Wiring Guide for Hot Rods and Race Cars

Automotive Wiring

In this video, you’ll learn wiring fundamentals for hot rods, drift cars, ratty muscle cars, and race cars. Jeremy from Wiring Rescue covers the wiring of a GM 3-wire 10si/12si alternator, a 12V automotive fuse box, and a starter circuit.

Using 200A Cole Hersee relays, we’ll power the fuse box and the starter. You’ll also discover the differences between continuous and non-continuous use solenoids, and the crucial role of diodes in your wiring setup. This video is your go-to guide for car wiring basics, including race car wiring, alternator wiring, automotive wiring, and more.

How To Wire a Basic Car Circuit: A Step-by-Step Guide

I’m, and today I’m excited to show you how I wired a basic race car circuit. This project includes essential components such as a master shutoff switch, an ignition switch, a neutral safety switch, a GM alternator, a solenoid, a fuse panel, and a starter. In this guide, I’ll walk you through each step to help you understand and replicate the process yourself.

Understanding Solenoids

Let’s start by discussing solenoids. A solenoid is an electrically controlled switch that allows a small circuit to control a larger circuit. There are two types of solenoids: continuous use and non-continuous use. For this project, I used a Cole Hersey 200 amp continuous-use solenoid (part number 24213). This type is suitable for powering up fuse panels and can handle prolonged use. In contrast, a generic Ford starter solenoid is designed for short bursts of electricity and is not meant for continuous use.

Setting Up the Fuse Box

The fuse box is a crucial component in this circuit. I chose a simple fuse box for demonstration purposes. The fuse box needs to be connected to the solenoid, which will control the power distribution. I attached a 194 bulb to the fuse box to visually indicate when the power is on.

Wiring the Solenoid

To wire the solenoid:

  1. Attach the main battery cable to the left terminal of the solenoid.
  2. Connect the power output from the solenoid to the positive terminal on the fuse panel.
  3. Ground the fuse panel using its designated ground section.
  4. Verify the connections by using jumper wires to activate the solenoid and power the fuse panel, turning on the light bulb.

Adding an Ignition Switch

Next, I integrated a basic ignition switch into the circuit. The ignition switch has four terminals: battery input, accessories, ignition, and start. The setup is as follows:

  1. Connect the battery input terminal to the power source.
  2. Link the accessory terminal to the solenoid.
  3. When the ignition switch is in the accessory or run position, it powers the solenoid, which in turn powers the fuse panel.

Installing a Master Shutoff Switch

A master shutoff switch is essential for safety and compliance with racing regulations. To ensure it functions correctly:

  1. Wire the master switch to control the power supply to the ignition switch and solenoid.
  2. Test the setup to ensure that turning off the master switch cuts power to the ignition switch, solenoid, and fuse panel.

Wiring the GM Alternator

I used a GM 3-wire alternator for this project. Here’s how to wire it:

  1. Connect the main power terminal on the alternator to the battery.
  2. Attach the voltage sensing wire (pin 2) to the main power terminal.
  3. Connect pin 1 (dummy light) to the 194 bulb and a diode.
  4. Ensure proper grounding of the alternator, especially if it’s mounted on a non-metallic surface.

Adding a Diode

A diode acts as a one-way check valve for electricity, ensuring current flows in only one direction. In this setup, it prevents the alternator from back-feeding power through the dummy light circuit when the master switch is off.

Integrating the Starter

The starter in this circuit is wired as follows:

  1. Connect the large battery cable from the solenoid to the starter.
  2. Attach a wire from the ignition switch to the starter solenoid.
  3. Verify the starter functions by turning the ignition switch to the start position.

Including a Neutral Safety or Clutch Switch

For added safety, a neutral safety switch (for automatic transmissions) or a clutch switch (for manual transmissions) ensures the engine starts only when the vehicle is in neutral or the clutch is engaged.

Items Used in this Race Car Circuit:

Video Chapters:

  • 00:00 How I wired a basic race car circuit
  • 00:50 The difference between continuous and non-continuous use solenoids
  • 01:41 What is the purpose of a solenoid?
  • 02:08 Overview of the fuse box I use in the video
  • 03:08 How to wire a Cole Hersee 24213 solenoid
  • 04:12 How to wire the universal ignition switch to the solenoid
  • 06:03 How to wire a battery shut-off/disconnect switch to a solenoid
  • 07:29 How to wire a GM 3-wire alternator
  • 10:06 What is a diode and how does it work?
  • 11:58 What happens if I don’t use a diode on my alternator?
  • 13:21 Why does a solenoid need a diode across the terminals?
  • 13:57 How to wire an automotive starter
  • 15:21 How to wire a neutral safety switch or clutch switch in a starter circuit
  • 16:39 How to wire a separate starter solenoid to a starter
  • 18:53 How to fix a starter that sticks out too long
  • 20:00 The importance of fuses and where I would put them

By following these steps, you can wire a basic race or custom car circuit with essential components for safety and functionality. Whether you’re preparing for a race or simply building your vehicle, understanding and implementing these circuits is a valuable skill.