Press brake dashboard illuminates

I currently own a 1997 nissan sentra gxe. My problem is when I press down on the brake the dashboard illuminates, the indicator lights light up as well as my brake lights. This also happens when the car is off, the keys are out of the ignition and the headlights are turned off. Also if I continue to press on the brake and open my car door, my car make a chiming sound as if I have left the keys in the ignition or left the headlights on. What is causing this problem? If anyone has an answer please give me a detailed response and solution so I can understand what is causing it. Thanks.