Door Ajar light on all the time. Disappears when brakes used.

Hello,
2004 Accent
For some reason the hatchback open light on the dashboard stays on. It is closed.
For some reason the light goes out when I touch the brake pedal.
Even when I remove the key and lock the car, the light still stays on.
Where is the sensor for the hatchback?
Any ideas? Thoughts?....etc...


Thanks,
Mark