Inertia Fuel Shutoff Switch: Description and Operation

Inertia Fuel Shutoff (IFS) Switch:

The inertia fuel shutoff (IFS) switch is connected in series with the fuel pump. The purpose of the IFS switch is to shut off the fuel pump in the event of a collision.

Typical Inertia Fuel Shutoff (IFS) Switch:

The switch 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 ramp and strikes a plate which opens the electrical contacts of the IFS switch and shuts off the fuel pump. Once the IFS switch is open, it must be manually reset to restart the vehicle.