Comparison of newer and older inertia fuel shutoff IFS switches

Inertia Switches cracked open
IF THE IMAGE IS TOO SMALL, click it.

Typical locations for Bronco & F-series include:
- firewall, between e-brake & brake pedals ('84-89)
- firewall, R side of trans tunnel ('87-91)
- R kick panel immediately below dash ('92-96)

. . . . .

The older switch is simply on-off (SPST); the newer switch (SPDT) changes its connection to the center terminal (PUMPS - COMMON) from the right terminal (SET - NC) to the left (TRIPPED - NO). If the left terminal is wired to a bulb with a hot feed, the bulb will light when the switch is tripped. '92-93 truck clusters have an unused bulb position for FUEL RESET, but they are miswired (probably to ensure it wasn't used, due to safety concerns about supplying voltage to the fuel pump motor after the IFS was tripped). The film circuit can be cut & rewired, and the IFS connector can be repinned to make the light work. '94-96 trucks have the SRS indicator in that position.

Owner caption November 2005 · Photo 1056 of 6546