BRAKELIGHT Switch
WARNING: This page is about a different car, the 1997 Mazda Millenia. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect brakelight switch connector. Using ohmmeter, check continuity between brakelight switch terminals. With brake pedal released, continuity should not exist. With brake pedal depressed, continuity should exist. If continuity is not as specified, replace brakelight switch.