Handbook 652 Body Electrical Diagnosis Power Source The EWD contains two resources for tracing power to a circuit– the Power Source System diagram and the Power Source (Current Flow Chart) . These two resources are sometimes confused with one another. Diagrams • The Power Source System diagram is a circuit diagram within the System Circuit Diagrams section. • The Power Source (Current Flow Chart) is its own section of the EWD. It is usually best to use both resources together . The system diagram provides power circuit details, while the flow chart provides an easy-to- understand overview of current flow.
Power Source System Diagram The Power Source System diagram shows the components and wiring from the battery through fuses and relays to all the system circuits. This diagram is one of the circuits in the System Circuit Diagrams section . The majority of the components in the Power Source System diagram are located in junction or relay blocks. This diagram is a good place to start looking for a problem if the circuit does not have power (after checking the fuse!) Technical Training 87