Handbook 652 Body Electrical Diagnosis Components and In the system circuit diagram, all loads, relays, switches, junction connectors, ECUs and ECU-type controllers, capacitors (noise filters), and isolation diodes are treated as components. Components are color coded light blue in the diagram. Connectors Component Location Each component is identified by a connector code and the component name. The codes appear in a list following the diagram with a cross reference to the page number in the Electrical Wire Routing section which shows the component ’ s location in the vehicle. 72 Technical Training