Wiring Harnesses Guide

Complete guide to creating, managing, and configuring wiring harnesses

Last updated: November 20, 2025

What is a Wiring Harness?

A wiring harness is the top-level container for your complete electrical design. It includes all connectors, connections, branches, lengths, and settings needed to document and manufacture your harness assembly.

Quick Navigation

Creating a Wiring Harness Editing Name & Description Measurement Units Cavity Description Propagation Column Visibility Duplicating a Harness Deleting a Harness

Creating a Wiring Harness

Start a new wiring harness project with a name, description, and measurement unit

Every harness design in EZ Wire starts with creating a new wiring harness. This establishes the foundation for all your connectors, connections, and documentation.

Creating Your Harness

1
Navigate to Wiring Harnesses from the dashboard
Click "Wiring Harnesses" in the main navigation menu
2
Click "Create Wiring Harness" button
3
Enter a descriptive name
Use clear, specific names like "1995 EG Civic K20 Engine Swap Harness" or "Custom Dashboard Harness"
4
Add a description (optional)
The description field supports multiple lines. Add project notes, version information, or any details that help identify this harness design.
5
Select your measurement unit
Choose between millimeters (mm) or inches (in). You can convert between units later if needed.
6
Click "Create Wiring Harness"
You'll be redirected to your new harness where you can start adding connectors

Note: The name and description can be edited at any time. The measurement unit can also be changed later with automatic conversion of all existing lengths.

Editing Name & Description

Update your harness name and description as your project evolves

Keep your harness details up-to-date by editing the name and description directly from the harness page.

Editing the Harness Name

1
Hover over the harness name at the top of the page
An edit icon will appear next to the name
2
Click the edit icon or the name itself
The name becomes editable inline
3
Type your new name
4
Press Enter or click away to save
Press Escape to cancel without saving

Editing the Description

1
Hover over the description area below the harness name
If no description exists, you'll see "No description provided. Click to add one."
2
Click the edit icon or the description text
A multi-line text area appears for editing
3
Enter your description
The description supports multiple lines and preserves formatting
4
Click Save or press Ctrl+Enter
Press Escape or click Cancel to discard changes

Pro Tip: The description appears on both the screen view and printed documentation, making it useful for version notes, build dates, or customer information.

Measurement Units

Choose and convert between millimeters and inches

EZ Wire supports both metric (millimeters) and imperial (inches) measurement systems. You can change between them at any time with automatic conversion of all existing dimensions.

Converting Measurement Units

1
Click the Settings button at the top of your harness page
Located next to the Print button in the harness header
2
Click the Measurement Unit button
Shows your current unit (e.g., "Millimeters (mm)" or "Inches (in)")
3
Review the conversion preview
The modal shows how your lengths will be converted
4
Click "Convert to [Unit]" to confirm
All lengths, connector strip lengths, and cut list calculations are automatically converted

Conversion Details: The conversion is non-destructive and uses standard conversion factors (1 inch = 25.4mm). You can convert back and forth without losing precision in most cases, though some rounding may occur.

Pro Tip: Choose the unit system that matches your wire supplier's specifications and manufacturing tools. This reduces conversion errors during assembly.

Cavity Description Propagation

Automatically copy cavity descriptions when creating connections

This powerful feature saves time by automatically copying cavity descriptions between connected cavities. It is enabled by default for all new wiring harnesses. When you create a connection and one cavity has a description while the other is empty, the description is automatically copied to maintain consistency.

Enabled by Default: This feature is turned on automatically for all new wiring harnesses. You can disable it in Settings if you prefer to manage cavity descriptions manually.

Managing the Setting

1
Click the Settings button at the top of your harness page
2
Check or uncheck "Auto-propagate cavity descriptions"
The checkbox will be checked by default. Uncheck it to disable automatic propagation.
3
The setting is saved automatically
Your preference is saved immediately when you toggle the checkbox

How It Works

Scenario 1: One cavity has a description

When connecting cavity A (with description "Injector 1 Signal") to cavity B (empty), the description is copied to cavity B.

Scenario 2: Both cavities have descriptions

Neither description is changed. Both cavities keep their existing descriptions.

Scenario 3: Both cavities are empty

Nothing is copied. Both cavities remain without descriptions.

Important: This feature only works when creating new connections. Modifying existing connections or changing wire types will not trigger description propagation.

Pro Tip: Since this feature is enabled by default, start by adding descriptions to cavities on one connector (like the ECU connector). As you create connections, the descriptions automatically propagate to all connected cavities, ensuring consistent documentation throughout your harness without extra effort.

Column Visibility

Customize which columns are displayed in your wiring harness tables

Control which information columns are visible in your connector tables to focus on the data that matters most for your specific workflow. All columns are visible by default, but you can hide any columns you don't need to reduce clutter and improve readability.

Available Columns

The cavity/pin number in the connector

Wire Number

Auto-generated or custom wire identification number

Wire

Wire gauge and type (e.g., 18 AWG TXL)

Color

Wire color and identification bands

Destination

Where the wire connects (connector and pin)

Wire Part Number

Manufacturer part number for the wire

Description

Custom description or signal name

Customizing Column Visibility

1
Click the Settings button at the top of your harness page
Located next to the Print button in the harness header
2
Find the "Visible Columns" section in the settings modal
You'll see checkboxes for each available column
3
Check or uncheck columns to show or hide them
Select which columns you want to display in your connector tables
4
Click "Save Settings" to apply your changes
Your column visibility preferences will be saved and the connector tables will update to reflect your selections

Note: Column visibility settings are saved per wiring harness, so each harness can have different column configurations based on your needs for that specific project.

Duplicating a Wiring Harness

Create a complete copy of an existing harness

Duplication creates a complete independent copy of your harness including all connectors, connections, branches, lengths, and settings. This is useful for creating variations or starting a new design based on an existing one.

Duplicating Your Harness

1
Open the harness you want to duplicate
2
Click the Settings button
Located at the top of the harness page next to the Print button
3
Click "Duplicate Wiring Harness"
Found in the Harness Actions section at the bottom of the settings modal
4
Confirm the duplication
Review the confirmation message and click "Duplicate"
5
You'll be redirected to the new harness
The duplicate has " (Copy)" appended to the name

What Gets Duplicated: Everything in the harness is copied including connectors with all their cavities and descriptions, all wire connections and wire types, all branches and lengths, tabs and organization, measurement units, and all harness settings. The duplicate is completely independent - changes to one harness do not affect the other.

Common Use Cases: Creating a left and right side harness, making a variant with different connectors, starting a new year/model based on previous design, backing up before major changes.

Deleting a Wiring Harness

Permanently remove a harness and all its data

Warning: This Action Cannot Be Undone

Deleting a wiring harness permanently removes all associated data including connectors, connections, branches, lengths, and settings. This action cannot be reversed.

Deleting Your Harness

1
Open the harness you want to delete
2
Click the Settings button
3
Click "Delete Wiring Harness"
This is a red button in the Harness Actions section
4
Read the confirmation warning carefully
The warning reminds you that this action is permanent and cannot be undone
5
Click "Delete" to confirm
You'll be redirected to the wiring harnesses list

Before Deleting: Consider duplicating the harness as a backup, or exporting your cut list and connector pinouts as PDF documents for archival purposes.

Best Practices

Tips for effective harness management

Use Descriptive Names
Include vehicle/project name, year, and harness type in the name for easy identification.
Add Detailed Descriptions
Use the description field for version notes, build dates, customer information, or revision history.
Leverage Auto-Propagate Cavity Descriptions
This feature is enabled by default to save time on documentation. Keep it enabled unless you have specific reasons to manage descriptions manually.
Customize Column Visibility for Your Workflow
Hide unnecessary columns to reduce visual clutter and focus on the information that matters most for each specific harness project.
Choose the Right Unit System
Match your measurement unit to your wire supplier and manufacturing tools to reduce errors.
Duplicate Before Major Changes
Create a backup copy before making significant modifications to preserve your working design.
Export Documentation Regularly
Print or save PDF copies of your cut list and pinouts as the design evolves.