Fuel pump cutoff switch: A fuel pump cutoff switch is a safety feature built into the vehicle, that allows you to project the flow of fuel from reaching the engine during certain scenarios. It cuts the fuel flow in a crash to stop gas from spilling and decrease the risk of fire. Switches of this kind, installed in many modern vehicles, are activated when the vehicle undergoes rapid deceleration or an impact of a certain severity which is equivalent to x g. In the event that fuel lines are ruptured in a crash, the cut off prevents more gas from spilling; making it as safe as possible.
Another integral part of the vehicle's safety system is the fuel pump cutoff switch, which is usually wired in series with the power to the electric fuel pump. When triggered, this cuts off the 12-volt supply to the pump and fuel flow is stopped almost simultaneously. A working cutoff switch can dramatically reduce post-crash fuel system issues leading to a fire by as much as 90%, for instance. Can be crucial, especially in high-speed crashes where fuel lines/tanks are most vulnerable to rupture
While a few vehicles have manual fuel-pump cutoff switches, most do not. In the case of a small nudge or inadvertent switch activation, the driver can simply toggle the switch back on and fuel will begin to flow again. Resetting the switch is normally a matter of seconds and means unnecessary tows or service calls when an engine won't start due to a non-critical trigger of the cutoff mechanism.
The gist of it is that during the 1990s Ford started installing fuel pump cutoff switches on many models as a reaction to several crashes and fires where leaks caused by bad construction had likely resulted in explosions. This decision heavily influenced the rest of the auto industry with other vehicle manufacturers often adopting these systems; fuel pump cutoff switches are a standard feature in many vehicles around the world having been inspired by this case. These switches improve safety, and reduce the potential liability of manufacturers in accidents.
If left addressed long enough, an inoperable cut-off switch can cause your vehicle to become a no-start, as it may prevent fuel from even reaching the engine even if there is not an emergency. A new switch, usually around $50 to $150, can diagnose and inversely return the car back to normal. Of course, this is an extra safeguard, especially for cars that are regularly used for long distance and/or high speed travel.
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