One problem related to brake light has been reported for the 1998 Buick Regal. The most recently reported issues are listed below.
Failure of driver's side rear brake light to activate when brake pedal is depressed. Passenger side and high mount light work fine. Left turn signal (which is the same wire as the brake) also works. After being ticketed for equipment failure, had diagnosed and found that the problem was in the multi function switch in the steering column. This switch controls turn signals, wipers, cruise control, etc. Since this occured I have noticed other general motors vehicles with the same or similar problem. This is a safety hazard and I wonder if any investigations have been done on this problem?.