a mate has a 2004 ibiza 1.2 with a strange electrical problem. the central locking is intermitant,but the main problem is when you start the car it fires up and runs normal until you press the brake pedal. then the dash lights start flickering on and off and if you switch the indicaters on with the pedal pressed the the indicaters start blinking real fast as if there is a bulb blown, but the second the pedal is released everything returns to normal. a real headmelter. i put a fault code reader on it and 2 codes came up,17925 main relay [j271] electrical malfuntion p1517. and 01336 data bus for comfort system static faulty. i cleared both codes but the data bus one keeps coming back everytime. anyone have any ideas? thank you.