25 Circuit Harness - Pro Series Truck GM Key

The 25 Circuit Harness - Pro Series Truck GM Key from Painless Wiring is a complete, customizable electrical solution designed for serious truck builders and restorers working with GM platforms. This harness simplifies the complexity of factory wiring by consolidating 25 individual circuits into an organized, modular system that accepts column-mounted ignition switches. It is ideal for frame-off restorations, modern engine management conversions, or simplifying aging electrical architectures.

The Pro Series design features a bulkhead firewall pass-through configuration, isolating engine bay circuits from cab wiring and reducing voltage drop across long wire runs. This is particularly important for trucks with high-demand components like fuel injectors and electric fans. The harness is designed with color-coded wiring and clearly labeled connectors that adhere to industry standards, making troubleshooting and future modifications straightforward.

This harness kit includes all necessary terminals, relay bases, and connectors, providing a reliable foundation for your electrical system. It is suitable for various GM truck models across multiple years, ensuring compatibility for a wide range of applications. Whether you're a professional builder or a dedicated hobbyist, this harness will enhance your vehicle's electrical performance.