Dishwashers use soap, sometimes in the form of soap tablets, to clean the dishes inside. The soap tablets are placed in a soap container in the dishwasher door, which opens up inside the washer once the washing cycle has started. There are a number of different reasons why your Whirlpool dishwasher might not be dissolving the dishwasher tabs, most of them having to do with the water supply.
Clean the washer arm
The spray washer arm sends water shooting around the dishwasher. If this arm is broken or clogged, it won't spray water, which would cause the tabs not to dissolve. The spray arm can be cleaned by removing the spray arm bolt in the centre and then rinsing it gently under hot water. Use a toothbrush to clean out the spray holes on the arm.
Soap container latch
Check the latch on the soap container located on the inside of the dishwasher door. If the latch is stuck, it won't open and the soap tablets won't get dissolved. Press on the manual opener on the door, usually by pushing it inward and releasing, to see if the latch opens on its own. Pour a small amount of vinegar on the latch and brush off any calcium deposits with a toothbrush.
Check that the water supply is on for the dishwasher. Most dishwashers are connected to the nearest supply, which is usually the kitchen sink. Trace the water supply hose from the dishwasher to where it meets the supply valve. Rotate the valve counter-clockwise to ensure the water is on all the way.
Bad inlet valve
The inlet valve is where the water supply hose connects to the washing machine. A device called a solenoid controls water entering the valve and cuts it off when signalled by the dishwasher circuit. If this valve is malfunctioning, it won't allow water into the machine for dissolving the soap tablets. Have the inlet valve tested by a professional and replace if needed.