2001 Pontiac Firebird Back Brake Lights & L/front Brake

Everything started with the police pulling over my wife. He pointed out that the brake lights in the back aren't working, except for the upper light on the trunk. After inspecting the bulbs and fuses we took it to the dealer and they gave it a diagnosis. Thier computer said that there was an open at the turn signal wiring which connects into the harness through the steering column. I've asked advise from others and they said to pull apart the connection to see if it's bad and I found nothing. While I was at work my wife took it to someone who told her it may be the switch at the pedal and she went to the auto parts store. The clerk promptly sold her a part and even installed it (Yes, my wife is good looking). She got maybe a mile down the road and the brakes seized. She called me and by the time I had gooen there nothing seemed to be wrong. I doulbe checked under the dash for any loose wires and to make sure the new part was in tight. We went on a quick trip around a few blocks and I could smell metal. When I checked, I could tell the brake had siezed. We made it back to the original spot and she followed me to a station. I cooled it with water and time and used the E-Brake to get it home, with no problems. I went and got an enclusive kit for brake and caliper, installed it and it still seizes and has no brake lights. Is this a computer stuck on stupid, 2 different wiring issues or 2 different????? HELP!!!