About the 1966 Mustang Wiring Harness

The 1966 Mustang wiring harness is a crucial component designed specifically for 1965-1966 Ford Mustang models. Featuring 22 circuits with factory connectors already installed, this harness uses Ford wiring color codes for straightforward installation. It includes an auxiliary circuit with a 20 amp relay, offering compatibility with accessories such as fog lights or an electric fuel pump. Additionally, the unique covered micro-fuse block provides protection for the electrical system, ensuring reliable performance.

Ideal for enthusiasts undertaking a restoration project or seeking to upgrade their Mustang's electrical system, this wiring harness offers a seamless fit and comprehensive functionality for the iconic 1966 Mustang.

Why a Modern Replacement Harness?

Original 1965-1966 Mustang wiring used cloth-wrapped wire, glass-tube fuses, and brittle insulation that becomes unreliable after 60+ years. A complete harness replacement is the right move for any serious restoration:

• Eliminates electrical fire risk from cracked or worn original insulation
• Modernizes fuse protection with ATC blade fuses (replaceable at any auto parts store)
• Adds high-output charging support with 175 amp Mega Fuse Kit and 6-gauge charge cable
• Enables modern engine swaps with HEI / EFI compatible ignition switch
• Provides clean foundation for adding modern accessories (electric fuel pump, fog lights, stereo)
• Maintains period-correct appearance with Ford factory color codes

Key Features of the 1966 Ford Mustang Wiring Harness

The 1966 Mustang wiring harness is tailored specifically for 1965-1966 Ford Mustang models and boasts a set of key features:

1. Direct Fit for 1965-1966 Mustangs: Ensures compatibility and easy installation without the need for extensive modifications.

2. 22 Circuits: Offers a wide range of circuits to accommodate various electrical components in the vehicle.

3. Factory Connectors Pre-Installed: Simplifies the installation process as many factory-style connectors come pre-installed on the harness, reducing assembly time.

4. Unique Covered Micro-Fuse Block: Provides protection for the electrical system components and ensures safety during operation.

5. Auxiliary Circuit with 20 Amp Relay: Enables the addition of accessories like fog lights or an electric fuel pump, enhancing the functionality of the vehicle.

Detailed Specifications of the 1966 Mustang Wiring Harness

Updated ATC Fuse Panel and Fuses:

• Modern ATC fuses are used throughout the system for reliable, accessible fuse protection. Replacement fuses are available at any auto parts store.

GXL Wire:

• High-quality, modern GXL wire is used throughout the harness for better heat and abrasion resistance compared to original cloth-wrapped wire.
• Each wire's function is labeled every 3 to 5 inches to make installation easier.

Pre-Built Dash Harness:

• Comes with an exclusive gauge cluster disconnect system. Compatible with both stock and aftermarket instruments (Auto Meter, Speedhut, Classic Instruments, etc.).

Engine and Front Light Harness:

• Features extra-long leads to facilitate custom routing and accommodate updated engine and transmission setups (small block Ford 289/302/351, Ford 5.0 Coyote swap, etc.).

Six-Way Power Accessory Plug:

• Provides a convenient power source for aftermarket accessories (modern stereo, GPS, dash cam, etc.).

Rear Body Wiring:

• Includes extra-long leads for custom routing, offering greater flexibility in installation.

175 Amp Mega Fuse Kit:

• Comes with a 6-gauge charge cable to support high-output charging systems and internally regulated alternators (1-wire, 3-wire alternators on modern 100A+ output).

Original-Replacement Connectors, Terminals, and Lamp Sockets:

• Ensures compatibility and easy integration with existing vehicle components and trim.

Headlight Switch:

• Includes a 26-amp internal circuit breaker for reliable performance.
• Comes with a new floor dimmer switch (the period-correct floor-mounted high/low beam dimmer).

Steering Column Adapter Kit:

• Mates with either stock 1965-1966 Mustang steering column or aftermarket tilt / telescoping columns (ididit, Flaming River, etc.).

Replacement Ignition Switch:

• Compatible with High Energy Ignition (HEI) and Electronic Fuel Injection (EFI) swaps. This is critical for builds upgrading from the original points distributor to modern HEI or running EFI conversion kits.

Compatibility of 1966 Mustang Wiring Harness

• Tailored for 1965-1966 Ford Mustang models (coupe, fastback, convertible)
• Ensures seamless fit and easy installation
• No need for extensive modifications
• Compatible with existing electrical components
• Simplifies restoration or upgrade process
• Optimizes performance of the vehicle's electrical system

What Is Included in the 1966 Mustang Wiring Harness Kit

Vehicle Compatibility

NOT compatible without modification: 1967+ Ford Mustang (different chassis architecture), 1964½ Mustang (limited compatibility, requires verification), Cougar / Falcon / Comet (different harness routing).

Condition and Inspection

This is a new restoration-grade wiring harness. Each harness ships with:

• All circuits continuity tested before packaging
• Factory connectors verified for proper insertion and retention
• ATC fuse panel function tested
• Insulation integrity verified
• Wire color codes verified against Ford reference

Why Buy From Vaz Auto Solutions

• Complete 22-circuit kit with 175 amp Mega Fuse, dash harness, ignition switch, headlight switch, floor dimmer all included
• HEI/EFI compatible ignition switch (for builds with modern ignition or EFI conversion)
• GXL wire throughout (period-correct color codes, modern reliability)
• Modern ATC fuses (replaceable at any auto parts store, no glass-tube hunting)
• Pre-built dash harness with gauge cluster disconnect (works with stock or aftermarket gauges)
• Direct fit 1965-1966 Mustang, no chassis modifications required
• Free shipping all 50 states, no hidden fees
• 15 day replacement warranty on manufacturing defects
• Mustang restoration experienced support team on the phone