The brake lights get power from fuse no 5. The turn signals also get power from this fuse so I assume the fuse is good since you say the turn signals work. This would indicate a problem with the brake light switch. If you follow the brake pedal arm up under the dash board you should find a switch that closes when the brake pedal is depressed. I'd start there and see if the switch is broken and not coming in contact with the brake pedal.