The fuel pump relay location on a 1991 Nissan 240SX is in the
engine bay fuse box. However, it's *not* usually labeled as "Fuel Pump Relay." It's often labeled as something more generic like a "EFI Relay" or might be simply numbered. You'll need to consult your owner's manual or a wiring diagram to identify the correct relay.
The fuse box is typically located near the battery, but the exact location within the engine bay varies slightly depending on trim level and options. You'll need to carefully examine the fuse box cover (often has a diagram) and possibly cross-reference the diagram with a wiring schematic.
