Whirlpool AWZ 412 over filling?

Hi I have an A Whirlpool AWZ 412 combination washer/dryer and it seems to constanly fill, it dosn't matter what programme setting its on or if i run it empty it just keeps on filling with water. I have cleaned out the door seals and the powder draw. ANy advise woud be much appreciated. My partner is an electrical engineer so is capable of replacing any parts required but cannot diagnose the actual fault. Any help or suggestions are greatly recieved. Thanks Sarah