Nissan 240SX Brake Light Switch

Ok, I have a 1989 Nissan 240SX Hatch/Fastback, Standard Transmission, approximatly 180K miles, 4cylinder,

The Problem I am having is with the brake light switch. I installed it and while I was instaling it I notice that where the button is supposed to push up againsed the brake pedal for some strange reason there is a hole! From my understanding with my car the button is always pushed in, until you push the brake wich releases the button and turns the brake light on, rigth now my brake lights are always on. So my question is how do I go about fixing this? Is it a defect or could the person who owned it before I did tamper with it. Sorry I dont have a picture, thank you very much for your time. :D