This 27 circuit 1973-1987 GMC/Chevy Painless wiring harness was designed to fit the trucks, Blazers, and Suburbans*, whether C10, C20, or C30. It features a factory style bulkhead connector, allowing for easy mounting of the fuse block in the factory location, and has many of the factory connectors already installed on the harness out of the box. Including connectors for: the headlight switch, dimmer switch, wiper motor, ignition switch, blower motor & switch, blower resistor, and instrument cluster. Each wire is custom printed with the circuit identification as well as using GM color codes for easy installation. Wire your Squarebody once and wire it right with Painless!