Q: where is innertia switch for 2008 lexus 250 is

The fuel pump cut-off function is integral to the circuitry in the PCM on this model. There is no separate, user serviceable switch. On this model, the only reason the fuel pump power cut-off feature will be invoked is if the air bags deploy. You can test for power to the fuel pump at key on, or during engine cranking. If there is no power, although you can use a factory scan tool to be sure power has not been cut, your no start condition (if that is what has prompted your inquiry) probably has a cause unrelated to any "cut-off". If your vehicle is presently not starting, and you want the required diagnostic steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a no start diagnostic. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.