wilde

Hi, I 've got a 96 xantia turbo diesel. Left the lights on and the battery went dead. I jumped it and the car started but when I start and finish the dips flash on and off for a minute or so. Also three days later (after a two hour drive the day before so I guess the battery would have been charged (no red no-charging light) my wife go in after work to find the battery too long for the car to start - AA came and charged it. Should I get a new battery? What's with the flashing lights? Many thanks in advance Brendan