To find the relay related to your fuel pump, you'll need to:
1. Consult your owner's manual: This is the best place to start. It should have a diagram of the fuse and relay box, identifying each relay.
2. Check the fuse box diagrams: The diagrams usually located inside the fuse box cover itself will show the relay locations and sometimes their function. Look for anything labeled "fuel pump," "EFI," or related terms.
3. Use a wiring diagram: A wiring diagram for your specific year, engine, and trim level is the most definitive resource. You can find these online through various automotive repair websites (often requiring a paid subscription), or at a parts store. These diagrams will show the complete electrical path for the fuel pump and the relays involved.
4. Use a multimeter: With the ignition on, you can test the power going to the fuel pump circuit. This will allow you to track down the potential failure point - a blown fuse, a bad relay, or a problem in the wiring itself. CAUTION: Work with the battery disconnected to prevent electrical shock.
In short: There's no single easy answer without more specific information about your truck's configuration. You need to consult your owner's manual or a wiring diagram.
