Why do the courtesy lights blink when the door is opened on a 1997 jaguar xj6

Just a guess, but there may be a partially damaged wire that gets stretched and then squeezed when opening and closing the door.....if the wiring is covered in a protective sleeve, it may require some checking to find out, it may also be just a loose connection at the lights or in the wiring circuit. i would check for a pinched wire between the door and body where the hinges are