If you have a newer-model Whirlpool or Kitchenaid dishwasher (also sold under the Kenwhore label), that’s not washing dishes very well, here’s whatcha do:
First, make sure your water fill level is adequate, should be just below heating element. The proper fill is 1.8 gallons, so if you want to see what a proper fill looks like before you proceed, use a pitcher and add 1.8 gallons of water to the empty dishwasher basin. Some other things to check for poor washing results on this page.
Ok, if that checks out, the next thing is to determine whether or not the wash motor is runnning. You’ll have to pull the kickplates off so you can check the voltage supply to the wash motor underneath. If the motor is getting voltage but it’s not running, or maybe it’s just making a humm noise but not circulating water, then you need a new wash motor. Or, for a few more shekels, you can save yourself some headache and replace the motor already assembled into the plastic housing as a complete assembly.
ON THE OTHER HAND, if the wash motor is running (and you have the proper fill level in the basin) but the dishwasher is leaving crud all over the dishes, then you can probably get by with just replacing the chopper (mascerator) and the check valve, shown here to the right (click the picture for an annotated view).
If you need help getting to the chopper assembly, grab some popcorn and enjoy this illustrative slideshow.
To learn more about your dishwasher, or to order parts, click here.