How to Clean the Brake Light Switch on a BMW

1. Spray the contacts of the BMW brake light switch with an electronic parts cleaner.
2. Scrub the contacts with a steel wool scouring pad to remove any corrosion on them. Do not scrub too hard; you only want to remove the corrosion and bring the contacts to a bright, shiny finish.
3. Spray the contacts with the electronic parts cleaner again. Spray all four contacts liberally, and let the brake light switch air dry.