(Moderators Note: With this posting the thread on the function of the Inertia switch is dead. All further postings will be deleted unless they contain additional info on this topic) It is my understanding that the inertia switch works in the event of a collision. The force of the collision throws the switch. This way if you get in a wreck the fuel pump is shut off. If you had a wreck without the switch the electric fuel pump would continue to run pumping fuel. If you had a fuel line burst you would increase your chances of a fire. Also, without the intertia switch your engine would continue to get fuel and run(unless there is some other safety device that will kill the engine). I would want to be sure to have this safety device... Just my 2 cents worth... Jeff