On a 1999 mercury mystique is the fuel cutoff switch controlled by fuse?

No, the fuel cutoff switch on a 1999 Mercury Mystique is not controlled by a fuse. It's typically part of the vehicle's safety system and is activated by a crash sensor (part of the Supplemental Restraint System or SRS). A blown fuse might prevent other electrical components from functioning, but it wouldn't directly control the fuel shutoff. If the fuel pump isn't working, it's more likely related to the inertia switch (which is often mistakenly called a "fuel cutoff switch"), the pump itself, the pump relay, or a wiring issue.