Navigator 4WD V8-5.4L DOHC VIN A (2000)
Inertia Fuel Shutoff Switch: Description and Operation
Inertia Fuel Shutoff (IFS) Switch
Inertia Fuel Shutoff (IFS) Switch
The Inertia Fuel Shutoff (IFS) switch is used in conjunction with the electric fuel pump. The purpose of the IFS switch is to shut off the fuel pump if a
collision occurs. It consists of a steel ball held in place by a magnet. When a sharp impact occurs, the ball breaks loose from the magnet, rolls up a
conical ramp and strikes a target plate which opens the electrical contacts of the switch and shuts off the electric fuel pump. Once the switch is open,
it must be manually reset before restarting the vehicle. Refer to the Owner Guide for the location of the IFS.