If your Whirlpool dishwasher's detergent dispenser stays closed during a wash cycle, your dishes won't be clean. Finding a fixing the cause of the problem is well within the reach of do-it-yourselfers. You may just need to clean the detergent dispenser door, allowing it to move freely. There is a part in the dishwasher door that triggers the opening of the dispenser door. If this piece stops working, you can replace it.
Understanding Possible Causes
If your dishwasher isn't opening the detergent dispenser door during wash cycles, there are two potential culprits. It's possible that the dispenser door is coated in old detergent and cannot move freely. If this is not the case, the mechanism in the dishwasher door that triggers the opening of the door is likely worn out. The trigger should cause the dispenser door to open at the appropriate point in the wash cycle and if it is burnt out, the dispenser door will not open.
Checking the Dispenser Door
If you can easily open and close the detergent dispenser door manually, then old detergent is not the problem. If the dispenser door sticks at all, clean it thoroughly until the door moves freely. If you see old, gummed up detergent in hard-to-reach places, pour warm water over the dispenser to dissolve the old soap. Place a towel or pan under the dishwasher door to catch drips as you clean. Run the dishwasher through a cycle to see if the dispenser door opens when it should.
Checking the Trigger
There are different models of Whirlpool dishwasher. Your specific model may have a solenoid trigger or a bimetallic warp trigger. Testing and replacing the trigger is the same regardless of the trigger type. You should turn off the power to the dishwasher before testing the triggering mechanism, either by unplugging the appliance or turning off the power at the circuit breaker. Unscrew the inner door panel to expose the trigger. Test the trigger with a volt-ohmmeter. If the volt-ohmmeter's needle doesn't move, remove and replace the trigger. Take the old part with you to the home improvement store to insure that you obtain the correct replacement part.