The fuel pump relay location on a 2007 Ford Explorer Sport Trac is
in the Power Distribution Box (PDB), also known as the fuse box under the hood. It's not always clearly labeled "Fuel Pump Relay," so you'll need to consult your owner's manual or a wiring diagram to identify the correct relay. The manual will show you the location of the PDB and which relay corresponds to the fuel pump.
Important Note: Without the owner's manual or a wiring diagram specific to your vehicle, pinpointing the exact relay is difficult and risky. Incorrectly manipulating relays can cause further damage. Using the owner's manual is the safest approach.