Updating your truck to an electric fuel pump? Wiring the pump to an on-off switch or to a simple ignition switched source isn’t the best idea. If an accident occurs, your pump would run as long as the switch is active. With the Fuel Pump Control Module, when the key is turned, the fuel pump turns on to prime the system in a three-second cycle, just like modern vehicles. Then the module uses the tach signal so the pump only runs when engine is running, giving you quicker start-ups and improved operating safety.