Electronic Automatic Climate Control System

Above is a schematic diagram of an (EATC) electronic automatic climate control system. Vehicle manufacturers create diagrams of the entire vehicle that can be complex and difficult to sort through, so they're broken down into system-specific diagrams called block diagrams, like the one above. Wiring diagrams show the wiring, connectors, and other system-related information. They're like road maps for the wiring routed throughout a vehicle.