The device, system and process of the present invention provides a means and method for assembly of wire harnesses. The present invention comprises at least a wire viewer module, a machine vision and optical character recognition module, a cassette tray platform, designed to receive and hold in place a cassette tray, having one or more receptacles designed to receive and hold in place a wire harness connector, having multiple pin-hole cavities illuminated from below or behind by a light source mounted on a two-axis translation stage or gantry to identify a cavity for wire insertion. Moreover, the present invention may further comprise a portable, computer-implemented system capable of executing a series of automated process steps designed to identify wire markings and guide the insertion of identified wires into wire harness connector pin-hole receptacles for assembly of a wire harness.