A 1988 Ford F-150 does
not have a readily accessible fuel pump shutoff switch as standard equipment. Unlike some later models, there wasn't a commonly installed, easily reachable switch for this purpose. You might find an inertia switch (intended to cut power to the fuel pump in a collision), but that's not a manual shutoff switch. The inertia switch location varied slightly depending on the trim level and body style of your specific truck, but it's typically under the dash or in the engine compartment. Refer to your owner's manual for the exact location.
To shut off the fuel pump in an emergency, you'd need to disconnect the fuel pump relay or the fuel pump fuse. These require more mechanical knowledge and accessing fuse boxes or relays.
