check if my led is on

thank you for your advice.
I am very sorry, I know my question seems to be very stupid (I'm a beginner) ... also my english (it's not my native language) ..
summary for what I want to do with my project is a bit like the mechanism of the car door. as soon as I close the car door, there is a light that goes off.
in my project, my goal is to put an motor at rest as soon as I close my other electric circuit contains a diode.