Exact OEM Reproduction Wiring Harnesses for Classic I. Built on a Wiring Harness Assembly Board. We assemble all our wiring harnesses on a wire harness assembly board to insure that each harness is consistently made accurately, with the correct: break-out positions, lengths of wires at each break-out, harness fastener locations, and taping locations. What is the wiring harness in a car? - Quora Mar 06, 2017A wiring harness in a car can be defined as a set of organized wires, connectors, and terminals which run all over the vehicle for relaying power and information. It plays a very important role in connecting different components of the car. The wi..