KTNNKG DC12V 500A High Current Master Battery Disconnect Switch Remote Control

what happens if you hit the button while vehicle is running? Will it damaged the vehicle computer fuel delivery etc?

Does the switch come with all the cables needed to connect to negative terminal of battery?

what is the default condition when there is no power applied? IE if the battery were dead would the device default to open or closed condition?

I need something that will cut the power to the positive side to stop a parasitic drain, does this device do this?