What was found
INFLIGHT AT CRUISE WE NOTICED THAT THE TAIL TANK FUEL WAS NOT TRANSFERRING. SHORTLY THERE AFTER WE RECEIVED TAIL XFER SOV OPEN FOLLOWED BY AUTO TAIL XFER CAS MESSAGES. WE FOLLOWED QRH PROCEDURE FOR TAIL XFER SOV OPEN AND WERE ABLE TO MANUALLY TRANSFER THE TAIL TANK FUEL UNTIL IT WAS EMPTY. REMOVED FUEL LEVEL SENSOR P/N 722599, S/N 3253, AND REPLACED WITH NEW FUEL LEVEL SENSOR P/N 722599, S/N 4849. IAW AMM 28-41-19. LEAK AND OPS CHECKS GOOD WITH NO DEFECTS NOTED.