Why does the brake light keep coming on?

Your brake fluid is probably low. Check it. Another possibility is that your brake pads are wearing out.

Some owners have found that the brake light comes on when it is cold out. However, this is often a symptom of another problem, and not the problem itself. Check your brake system to make certain.

Another possibility is some malfunction in the antilock braking system of your car. If you find your fluid is ok, have the ABS system checked out. It has been reported that 1991 cars may occasionally experience a glitch in a wheel sensor, causing the ABS system to reset.

Still another possibility is that you are accidentally bumping the parking brake handle with your right knee. This can happen to taller people.