Should the fuel pump switch be up or down on a ford explorer 1998 model?

There's no single "fuel pump switch" in the sense of a readily accessible on/off switch like a light switch on a 1998 Ford Explorer. The fuel pump is controlled by the computer (Powertrain Control Module or PCM). There might be an inertia switch (a safety device that cuts power to the fuel pump in a collision), but that's not an on/off switch for normal operation. If you're having fuel pump issues, you need to diagnose the problem using a diagnostic tool or by checking fuses and relays, not a simple up/down switch.