Bronco Wiring Harness - Centech Wire If you own a 1966 to 1977 Bronco, the BR-10 is the harness to buy. These brand-new wires are labeled and able to withstand up to 275-degree heat. The kit also includes the accompanying late-model electrical switches and connectors. An illustrated installation manual makes wiring your Bronco easy. Early Ford Broncos & Trucks - centechwire Adapts Centech BR-10A Harness to Stock Bronco 66-77 Ignition Switch Adaptor for BR-10 Harness to stock early Bronco Park and Turn lamp We've improved our BR-10 harness to make it easier to install your C4 or C6 transmission PLUS we've added direct wiring to the tail lamps to simplify that wiring.