half way up the brake pedal are is the brake light switch, the pin from the switch should be be pushed in by a plastic tab that is mounted on the brake arm. while you are under the dash looking at the switch, push the pedal down if you do not hear a click the tab on the arm broke off. holding the pedal down see if you can manange to push the switch in and have someone in back let you know if the lights shut off. if so that is your problem. what you will want to do is finish breaking the plastic piece from the arm, there should be a hole completely through. get a phillips head screw that will fit all the way through and put a nut on the back side to tighten it down. release the pedal and look to see if the pin on the switch pushes in, you will will hear it click, which means the circuit has been cut. this will fix your problem. good luck, let me know the outcome.