Vehicle repair gurus find Freightliner wiring schematics and diagrams on the Freightliner website. These diagrams are sorted into various categories based on the electrical components of the vehicle, such as the starter, horn, suspension dump, fog lamps and warning lights, as of 2015.
For example, grounding module documents include four separate PDFs that show how to place wires from the chassis and exterior front wall into the grounding module. Other wires go to tail lights, pumps and the trailer to provide grounding for the truck's electrical systems. Each section of diagrams explains how to connect wires for one type of Freightliner truck, such as the business class M2 body.