To find the correct wire, you must consult a wiring diagram specific to your 1993 Ford Ranger. You can usually find these diagrams in a repair manual for your vehicle. These manuals are available online (often as PDFs) or at auto parts stores. The diagram will show you the wire color and its location at the instrument cluster connector or the fuel sending unit.
Looking at the wiring harness itself is risky without a diagram, as incorrectly identifying a wire could damage your vehicle's electrical system.
