Cause 1
Drain Pump
The drain pump uses an impeller to force water through the drain hose. If the drain pump motor is not working, the dishwasher won’t drain. To determine if the drain pump is defective, check the pump motor for continuity using a multimeter. If the motor does not have continuity, or if is getting power but won’t run, replace the drain pump. Drain pumps are not repairable—if the drain pump is defective, you must replace it.
Cause 2
Drain Impeller
The drain impeller pushes water through the drain hose and into the garbage disposer or drain line. If the impeller is broken, replace it.
Cause 3
Drain Solenoid Kit
The drain solenoid opens the drain valve to allow the water to exit the dishwasher. If the drain solenoid fails the valve will not open causing the dishwasher not to drain.
Cause 4
Drain Valve
Over time, the drain valve can get clogged with debris. To ensure that water can flow through the drain valve, clean out the valve. If the drain valve is clear of debris but it still won’t actuate, replace it. Drain valves are not repairable—if the drain valve is defective, you must replace it.
Cause 5
Pump and Motor Assembly
The motor drives an impeller to force water out of the drain hose. If the motor runs during the drain cycle, check for a blockage in the drain line. If the motor won't run during the drain cycle or if it just hums when it should be running, the pump and motor assembly might need to be replaced.
Cause 6
Clogged or Improperly Installed Garbage Disposer
If the garbage disposer was installed recently, the drain plug may not have been removed. All garbage disposers are sold with a solid plug in the drain tube. If the dishwasher is not connected to the garbage disposer, the plug must remain in the drain tube. However, if the dishwasher is connected to the garbage disposer, the plug must be removed. If the garbage disposer wasn't replaced recently, it is possible that the disposer is clogged. Remove the dishwasher drain hose from the disposer and clean out both the fitting on the disposer and the end of the drain hose. These are the most common places to find an obstruction if the dishwasher won't drain.
Cause 7
Drain Hose
The drain hose might be clogged. To unclog the drain hose, remove the drain hose from both the dishwasher and the sink drain and clean it out. The drain hose is most commonly clogged near the garbage disposer or dishwasher drain branch tailpiece.
Cause 8
Check Valve
The check valve prevents water from returning to the dishwasher after it has drained. If the valve gets stuck closed, it will prevent the water from draining. If the check valve is stuck closed, try cleaning it out and then replace it if necessary.
Cause 9
Check Ball
The check ball is a small plastic ball in the check valve that prevents water from returning to the dishwasher after the dishwasher has drained. If the check ball gets stuck, it will prevent water from draining through the check valve. If the check ball is stuck, try to free it.
Parts
Cause 10
Water Pump Belt
The water pump belt might be worn out or broken. However, because very few dishwashers have a water pump belt, you should search for your model number to determine if it has a water pump belt. To access the water pump belt, remove the lower panel. The water pump belt is located on the bottom of the motor. If the water pump belt is broken or worn, replace it.
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3 Comments
Come back after you have used your multimeter
by mayer
I have the same problem. Any resolution yet? I have checked the power to the drain pump during the drain cycle but there is no power to the pump. Everything else checks out. I am wondering if it is the controller.
by Steven Macaluso
I too have the same problem with my Neff 7405 dishwasher - no power to the drain pump.
I have renewed the drain pump and tested, (by applying mains power to it), that it works. However, the drain pum does not turn on during the wash cycle.
Does anybody out there have any ideas as to what this could be?
by Jeff Potts