Where is the fuel pump relay on 2001 ford explorer 4.0 L. engine?

The fuel pump relay location on a 2001 Ford Explorer 4.0L is in the Power Distribution Box (PDB), also often called the fuse box under the hood. It's *not* always labeled directly as "Fuel Pump Relay," so you'll need to consult your owner's manual or a wiring diagram. The manual will show you the location of the PDB and may have a legend identifying the relays.

The relay itself is usually a small, square or rectangular component. You might need to remove the cover of the PDB to see all the relays. Always disconnect the negative battery cable before working with any electrical components.

If you can't locate it using the manual, a search online for "2001 Ford Explorer 4.0L fuel pump relay location diagram" might yield a helpful image. Be sure to double-check the year and engine size to ensure the diagram applies to your specific vehicle.