Wiring & Ignition Systems

Tom's Offroad carries a replacement wiring harnesses for the 1966–1977 early Bronco, manufactured by Painless wiring harnesses. This kit includes the engine harnesses, dash harnesses, and taillight wiring kits. Painless Performanceis ideal for restomod builds or heavily modified trucks with added electrical components.

Original early Bronco wiring harnesses are 50+ years old and commonly suffer from cracked insulation, corroded connections, melted wires from heat, and previous owner repairs that create fire hazards. A failing wiring harness is one of the leading causes of classic truck fires. Replacing the harness proactively during a restoration is far less costly than tracing electrical gremlins after the fact.

Replacing an early Bronco wiring harness involves methodically removing the old harness section by section, labeling all connections before disconnecting, routing the new harness along the same paths, and connecting each circuit in sequence. Using a wiring diagram specific to your year is essential. A complete harness replacement is a multi-day project at minimum and is best done during a full restoration when the dash and interior are already removed.

Painless Performance 28-circuit harness kits are the most popular aftermarket option for early Bronco restomod builds. They include a fused circuit breaker panel, color-coded wires, and detailed instructions.

Removing the dash harness from an early Bronco starts with disconnecting the battery, then removing the instrument cluster, radio, dash switches, and heater controls to access the harness routing. Photograph or sketch all connections before removing any connectors. The harness typically routes through grommets at the firewall, remove these grommets carefully to avoid tearing them.