The inertia switch should be in a little flap behind the kick panel in the front passenger side footwell. Its quiet a big black box with if my memory serves me right a white plunger so it should stand out a fair bit down there.
I'd deffinatly have a look at your fuse box area if the relay isn't there some ones played funny buggers with it some where along the line.
If you take the kick trim off the drivers side you should be able to trace/follow where the fuel pump wires go to and see what the crack is with them.