I have a Ford F 150 1987 I replace the fuel filter and fuel pump and it still won't click over

try looking for "FUEL CUT OFF SWITCH".. it may be underneath the dash on the drivers side... look for a switch with a red button pointing straight up kinda recessed in the black switch.. push it til it clicks then start the truck. If it runs and dies or doesn't start at all that was it. You can just unplug it too.. I believe to turn it back on you have to raise the red button with a pick or screwdriver.. or if you unplugged it.. plug it back in.

this one is for 1999 f-150 its in the right hand side kick panel, under the glove box, you may be able to see it without removing the trim piece if not that trim piece just pops off and it should be right there. it will have two wires going to it and the button is red

also known as inertia cut-off switch