possible causes wrong bulbs in lamps. wired wrong way round ie the tail lights wired to the brake lights.bad earth at lamps causing back flow to earth through tail bulbs. there is also a possibility you have two seperate faults ie the brake light switch above the brake pedal could be faulty putting your brake lights on all the time, and a faulty earth or broken wire or bad connection to the rear lights.
brian moore, October 2005
