The fuel pump is controlled by the computer (Powertrain Control Module or PCM) and various safety systems. The pump will stop if:
* The ignition is turned off: This is the primary way to stop the fuel pump.
* A crash occurs: Deployment of airbags or other crash sensors will cut power to the fuel pump.
* A fault is detected: The PCM monitors various engine sensors and will shut down the fuel pump if it detects a problem (e.g., a major engine malfunction).
If you need to disable the fuel pump for safety reasons (e.g., a fuel leak), you'll need to disconnect the electrical connector to the fuel pump relay or the fuel pump itself. This is dangerous and should only be done by someone experienced with auto repair, as working with fuel systems carries significant risk of fire. Disconnecting the battery's negative terminal will also stop the fuel pump, but it's not instantaneous.
In short, there's no readily available switch. The best way to stop the fuel pump is to turn off the ignition.
