73 87 Chevy Truck Wiring Harness Diagram

Hello and welcome to this article about the 73 87 Chevy Truck Wiring Harness Diagram. In this comprehensive guide, we will explore the intricacies of the wiring harness diagram for these classic trucks. Whether you are a truck enthusiast or a DIY mechanic, this article will provide you with all the information you need to understand and work with the wiring harness diagram.

1. Introduction to the 73 87 Chevy Truck Wiring Harness Diagram

The wiring harness diagram is a visual representation of the electrical connections in the truck. It outlines the various wires, connectors, and components that make up the truck’s electrical system. Understanding the diagram is crucial for troubleshooting electrical issues, installing new components, or modifying the wiring in any way.


  • Provides a clear and organized overview of the truck’s electrical system
  • Helps in diagnosing and fixing electrical problems
  • Enables easy installation of aftermarket components


  • May be overwhelming for individuals with limited electrical knowledge
  • Requires attention to detail and careful interpretation
  • Does not account for variations or modifications made to the original wiring

2. Understanding the Wiring Harness Diagram

The wiring harness diagram consists of various symbols that represent different electrical components and connections. These symbols include lines, dots, squares, circles, and letters. Each symbol has a specific meaning and represents a particular wire or connector. By referring to the diagram, you can identify the wires’ colors, gauge, and their corresponding functions.

3. Common Wiring Harness Diagram Components

The wiring harness diagram typically includes the following components:

Component Description
Battery Provides power to the electrical system
Ignition Switch Controls the electrical power to the ignition system
Fuse Box Holds fuses that protect different electrical circuits
Starter Engages the engine when the ignition key is turned
Alternator Converts mechanical energy into electrical energy to charge the battery
Lights Includes headlights, taillights, brake lights, and turn signals
Wipers Controls the windshield wiper system
Heater and Air Conditioning Controls the truck’s climate control system
Radio Manages the truck’s audio system

4. Troubleshooting Electrical Issues

When facing electrical problems in your 73 87 Chevy Truck, the wiring harness diagram can be a valuable tool for troubleshooting. By following the diagram and tracing the wires, you can identify any damaged or disconnected connections. Additionally, the diagram allows you to check the correct voltage, resistance, and continuity in various circuits.

5. Installing Aftermarket Components

If you are planning to install aftermarket components in your truck, such as a new stereo system or lighting upgrades, the wiring harness diagram is essential. It helps you understand the existing wiring and locate the appropriate connections for your new components. By following the diagram, you can ensure a proper and seamless installation process.

6. Modifications and Alternatives

While the 73 87 Chevy Truck Wiring Harness Diagram is specific to these trucks, there are alternative resources available. Online forums, repair manuals, and aftermarket wiring kits provide additional diagrams and instructions for modifications or upgrades. These resources cater to specific needs, such as engine swaps, custom lighting setups, or trailer wiring.


In conclusion, the 73 87 Chevy Truck Wiring Harness Diagram is a valuable tool for anyone working with these classic trucks’ electrical systems. It provides a clear and organized overview of the wiring connections, enabling troubleshooting, installation of aftermarket components, and modifications. By understanding the diagram, you can confidently navigate the electrical system and maintain your truck’s functionality.

Frequently Asked Questions (FAQ)

Q: Can I use the same wiring harness diagram for other Chevy truck models?

A: While some components and wiring may be similar across different Chevy truck models, it is recommended to consult the specific wiring harness diagram for your truck to ensure accuracy.

Q: How can I obtain a wiring harness diagram for my 73 87 Chevy Truck?

A: Wiring harness diagrams can be found in repair manuals, online forums, or by purchasing aftermarket wiring kits specifically designed for these trucks.

Q: Can I modify the wiring harness in my truck?

A: Yes, the wiring harness can be modified to accommodate aftermarket components or to suit specific needs. However, it is crucial to follow the correct wiring standards and consult the appropriate diagrams to ensure safe and proper modifications.