Has anyone come across a flat battery on a newish car, two year old? I recently noticed that my brake lights come on once Ive locked the car up. I later on found out that it was to do with a faulty brake light switch, which I havent replaced yet. I managed to jump start and drive the car around to charge the battery up. Then after about a day or so the battery goes flat again. Ive made sure that none of the lights are on before I lock up, I cant figure out what going on. Any ideas would be great!