Not sure what you found, but it does'nt sound like an inertia switch to me.

Nice that Subford is going to post the wiring diagram. After he posts it check the color coding on the diagram and compare it to the wires on that "inertia switch"

At the inertia switch you need to connect your voltmeter to the wire from the pump relay & any good ground.Turn the key to RUN & you should see 12 volts for 2 seconds.