Seems like something wrong with the break light switch, this is usually located under the dash, near the top of the brake pedal. it’s should attached to a small bracket that holds the switch, If u managed to find the switch, check to make sure that the brake light switch's electrical connection is firmly attached and that all of the wires connecting to the brake light switch are in good condition..this happenes to my lancer sometime back n i had to replace the switch...good luck mate!