Ford F150 - inertia switch (fuel shutoff)

I cannot locate this device!
It is not under the right of left side kick panels, nor behind the glove box or any where under the dash on the drivers side that I can see. Do 4x4 noyt have these?
This is an 89 5.8 4x4 xlt Lariate

I've heard that on some years they are mounted up under the dash near the brake pedal, hidden fairly well. Sorry I can't be of more help.

This is the early location:



This is the late location:



Very few trucks have them mounted to the firewall just to the R of the hump, i.e., at the front L of the passenger footwell.

does the inertia switch have 2 wires or three? On my truck it looks like someone removed it as part of the propane setup. There is a place where something was removed, and there is a pink/blk wire and a solid brn wire thathave been routed to a alternate fuel module on the firewall. Can I join these two wires and bypass the whole works? At this point I plan remove the ALternate Fuel Module and attempt to restore things to a somewhat stock state.

Some have 2; some have 3. '89 fullsize only have 2. Solid Br wires on Fords are almost always the parking light circuit. Check the Haynes manual wiring diagrams for the IFS wire colors.