What happens to a modern hot rod (Stang, Camaro, Challenger or any modern car) when you "cut" power to the ECM, TCM, NAV, Blue Tooth (my radio presets!) etc,etc,etc when the car is running just to satisfy the tech guy. I don't think the "modern" electronics would like it much. Also, would this hurt a custom ECM tune?
All modern cars are federally mandated to have an inertia fuel cut off switch. Crash the car, put some G's on and the pump is deenergized.
To check the master (battery) cut switch all that is needed is a multimeter or a test light.
Please, leave my eletronics alone. I can mess them up on my own thank you very much.