I'd start by checking that the bulbs haven't blown and that you have a voltage present when the brake pedal is de-pressed. If you look in your owners manual, you should be able to find the appropriate fuse, check this to ensure that it hasn't blown. If the fault still exists, then I suspect you have a problem with the brake pedal switch. You can check the operation of this with a continuity tester. Purchase a Haynes manual for location and wiring schematics.
Mike, September 2004