A clarifacation on the inertia switch. It's purpose is in the event of an impact it opens the ground circuit to the fuel pump. The car does not have to roll over to activate it. The inertia switch has a second function, it will unlock the doors if the door lock circuit is working and correctly hooked up. In the event of a rollover there is a valve in the filler neck to the fuel tank to keep the fuel from comming out. There was a recall because the origional design was too sensitive and would shut the car down without an accident. All fuel injected cars are now required to have an inertia switch in the event of an accident. They are also required to have a circuit that will shut the fuel pump off if the motor is not running hence the need for the RPM relay.Many cars have been rewired incorrectly because people don't understand the need for these safety items but in an accident you don't need fuel dumped all over and create a more dangerous situation. David Teitelbaum vin 10757