If your dishwasher is not draining water then there could be a clog in the drain hose, pump or possibly a defective part. Here’s how to troubleshoot and what parts could be causing the problem.
WARNING! Before attempting to work on any appliance, make sure that all power (electricity) and utilities (water and gas) have been turned off and/or disconnected on the appliance. Read this before you start any repair.
The dishwasher drain pump forces the water out through the drain hose. Depending on your dishwasher’s model, you could have a reversible pump or a direct-drive pump. Disconnect the pump from underneath the dishwasher’s basin. Be sure to have a bucket and towels on hand to catch any residual water in these parts. Remove the drain hose and check for any clogs in the pump or in the ends of the drain hose connected to the pump.
The drain pump can be tested for continuity with a multimeter. If there is no continuity, then replace the pump.
Pump and Motor Assembly
The motor drives an impeller to drain the water from the dishwasher. If the motor does not run or only hums then the pump and motor assembly needs to be replaced.
There may also be a clog at the other end of the dishwasher’s drain hose as well, especially where it attaches to the garbage disposer. Also, if you notice any cracks or leaks from the hose, replace it with a new drain hose.
In dishwashers with a single-direction motor, a drain solenoid opens and allows water to drain from the dishwasher. If this part is bad, the solenoid will not open and water will remain in the dishwasher. Use a multimeter to test this part for continuity and replace if needed.
Check Valve Flapper and Check Ball
The check vale prevents water from returning to the dishwasher basin after it’s been drained. Sometimes the vale becomes stuck shut. Try locating and cleaning the valve or consider replacing it if it no longer functional.
The check ball works in much the same way as the check valve does – it prevents water from re-entering the machine once it has been drained. Sometimes the ball can become stuck and prevent water from draining. Free the ball and see if this fixes the problem.