Turn off the power supply to the dishwasher from your kitchen's circuit breaker.
Open the dishwasher door, then slide out the bottom rack to fully remove it from the unit.
Remove the bolt on the base of the spray arm in the center of the dishwasher, using a wrench.
Remove the spray arm from the unit. Pull out the screen below the spray arm.
Remove the two screws on the mounting plate that hold the water pump in place.
Pull upwards on the water pump and the upper impeller will be exposed. Remove the bolt on the pump using a wrench.
Disconnect the impeller, the fan blade part on the water pump, and then inspect it to see if it needs to be repaired.
Place the impeller or new impeller part back onto the water pump. Reinsert the bolt onto the water pump.
Reinsert the two screws into the mounting plate to hold the water pump back into place.
Place the screen back on over the water pump, then place the spray arm back into the center of the unit.
Reinsert the spray arm bolt and slide the bottom rack back into the dishwasher. Close the door and turn the power supply back on from the circuit breaker.