Parts manuals include detailed schematics of every major system that makes up your vehicle. The drawings include individual parts as well as parts groupings. Every parts schematic has a corresponding page that lists the part number, quantity and description of the part. These manuals are helpful for understanding how an assembly goes together, for ordering parts and restoration. While many parts diagrams are available online, having a parts manual in paper format is a handy reference and in many cases provides a clearer understanding of what is shown in the service manual. A parts manual is a great compliment to the service manual.