Yeah, the inertia switch is basically like a circuit breaker. Just press it in and if you hear it click, it was tripped, otherwise that's not your problem. It's also possible for it to just be bad, though.
If the 93 is anything like the 89, which I think it is, the fuel pump relay is under the drivers seat. It's mounted to the floor. I would think that when you turn the ignition switch on that it should click.
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351W 89 Mustang GT Convertible