LED still wont work on Rear camera even after fitting new camera

had a water issue with my iPhone4 a year ago, some water got into phone at the rear camera end and flash/led has never worked since, camera continued working ok, replaced the rear camera yesterday after purchasing a new one from ifixit, when i replaced camera and switched on phone again i went to itorch and switched on, the led fickered once and that was as far as it went, tried taking picture with flash on and no flash happened, wondering if anybody has had this problem or knows an answer, cheers