The brake lamp switch has three internal switches with a single, six blade harness connection at one end. When the
brake pedal is in the released position, the plunger on the outside of the brake lamp switch is forced inward, which
opens the circuit. When the brake pedal is pressed the plunger is released, and the circuit is closed. This action
completes the brake lamp circuit, and allows the brake lamps and center high mounted brake lamp to illuminate.
No switch? How long have you had the car?
The above is from the shop manual (on this site) have a look.