Handbook 652 Body Electrical Diagnosis Junction Blocks The letter part of the J/B ID in the oval indicates a specific connector to the junction block, and the number beside the oval is the pin number in that connector. (cont.) • The J/B ID appears in a cross reference list following the system circuit diagram with the page number of the J/B diagram in the Relay Locations section. Junction Block Location The Relay Locations section of the EWD provides several kinds of information about junction blocks, including: • Part locations • J/B diagrams • Connector diagrams • Inner circuit 78 Technical Training