This manual contains the detailed wiring diagrams for the Volvo FH(4) series equipped with a dual-stage turbocharger. It provides comprehensive electrical schematics, including connections and circuits essential for diagnosing, repairing, and maintaining the advanced turbocharging system and related components. Designed for technicians and engineers, this guide ensures accurate troubleshooting and proper maintenance of the dual-stage turbo system, making it an essential tool for professionals working on these Volvo FH(4) trucks.