Revive your Mustang’s electrical reliability with a top-quality 1966 Ford Mustang underdash harness. This critical wiring component serves as the backbone of your vehicle’s interior electrical system, powering essential features like gauges, lights, switches, and more. Over time, original harnesses can suffer from brittle insulation, corrosion, or faulty connections—leading to frustrating electrical issues and safety concerns. Our precision-crafted replacement harnesses are made to factory specifications, ensuring a perfect fit and plug-and-play installation. Whether you're restoring your classic to showroom condition or eliminating hard-to-trace wiring problems, this underdash harness is the dependable solution your 1966 Mustang deserves.