Brake light swiches are normally found underneath the brake pedal. Have a look and you should see a plastic cylinder with a spring inside it, this, when depressed turns the brake lights on. Removal is pretty easy, all i had to do was pull it out/unscrew it. Pop down to your local vw garage, get one, replace and make sure you have a friend there to check the lights while you adjust the switch.
James Best
January 2009