Whirlpool dishwasher du1148xtpqs

Question

my dishwasher is about three years old water will come into the machine and will drain out when i push cancel when it goes into the wash cycle all it does is hum. i have had the motor out of the machine and everything seems to be moving freely.i can put the machine into check mode by pushing heated dry and high temp wash and it has the same problem when i first found the problem the wash light was flashing. the dishwasher had been making a loud noise for a while i am sure i could replace whatever part is faulty if i knew what one it was