That amp under warranty??If so send it back,and try to get another ..Ill Bet that that fan has came off/ or is not stable, and moved do to vibration, so its not laying flat any more,and turning/against the face/wire inside??How about moving your box a little bit up away from the amps as well??Fan is prob not sitting in its original location inside of the amp,and is hitting against something??Dont break the seal on it,and ruin the warranty.You will need existing box/all paper wk,ect. As the amp came to retrieve warranty at most places/All original