Dishwasher Humming but not Working? 4 Main Reasons & Solutions

The dishwasher is one of the best modern-day kitchen appliances. The basic working of the dishwashers is similar despite the model, brand, or inner shape.

A dishwasher has two functions: It uses soapy water to clean nasty spots on the dishes. Drying the dishes is achieved via hot air or hot water at the end of a cycle to maintain the spotless beauty of our dishware.

A humming sound is heard throughout its operation. It is quite normal and indicates the proper functioning of the dishwasher. Sometimes we hear the humming sound but dishes come out dirty.

It can be due to many reasons. In this article, we will discuss all those causes that result in dishwasher humming but not working. I will also provide their solution.

Dishwasher humming but not working

The main reasons why your dishwasher is humming but not working are:

∙         Pump motor Failure

∙         Blocked inlet valve

∙         Damaged float switch

∙         Malfunctioning door switch

All these factors cause the incomplete filling of the dishwasher. Now we will discuss these reasons in detail.

Pump Motor Failure Causing Humming of Dishwasher

Dishwasher Humming but not Working? 4 Main Reasons & Solutions

Humming sound without filling, especially seen after a break of at least 7 days, is a clear-cut indication of pump motor failure. It is recommended to use a dishwasher at least once a week. It keeps the dishwasher seals moist and prevents them from sticking together.

Pump motor failure causes incomplete filling of the drum. Insufficient water in the drum stops the wash cycle and overall working of the dishwasher is disturbed.


To get rid of this situation, you can follow these simple steps:

∙         Remove the dishes and other utensils from the dishwasher

∙         Remove the residual water if there is any.

∙         Make a solution of 4-5 ounces of citric acid and a glass of hot water. Citric acid is easily available at supermarkets.

∙         Pour this solution into the sump area (rear area at the bottom of the tub) and wait for 15 to 30 min.

∙         Place the utensils and start the dishwasher

Blocked Inlet Valve Causing Humming of Dishwasher

Dishwasher inlet valve

Lime formation constricts the inlet valve and halts the complete filling of the drum. Lime formation in the inlet valve is caused by hard water. If your area has a known hard water problem then the same problem can cause your dishwasher to malfunction.

The results are the same as described before.

Inlet valves connect the dishwasher to the main water supply. Water flows into the dishwasher tub through the small inlet. Its blockage renders the flow of the water into the dishwasher and the wash cycle cannot start. The most logical step in this situation is to inspect the source of water supply and means of connections.


Lime deposition is a slow process and it will reflect itself in the slowly declining performance of your dishwasher.  You can easily check and replace your inlet valve by following these steps:

∙         Turn off the electrical supply

∙         Remove the front access panel

∙         Locate the water hoses first and the inlet valve is located behind it

∙         Inspect it for any lime formation and try to scrap it off

∙         If the working of the dishwasher improves, your valve is still in working condition

∙         If working remains the same, you need a replacement

A permanent solution to this problem is changing the water source but it is difficult for many people. So I recommend using a Zeolite filter. It removes the hardness and prevents lime formation.

Damaged Float Switch Causing Humming Of Dishwasher

The float switch controls the inflow of the water. Any damage to the float switch will signal the inlet valve and it will stop the inflow of water immediately.

A float switch is present inside the tube and it is connected with the inlet valve. It functions to control the level of water in the dishwasher. When the water reaches appropriate levels, it sends a signal to the inlet valve. The Inlet valve closes on that signal and stops the inflow of water.

One can easily imagine the damage to the float switch can result in inappropriate signaling. The Inlet valve remains close and the dishwasher does not have water for cleaning.


You can easily check for visible damage after locating your dishwasher switch. Replacement can be easily found on Amazon. You must seek a professional’s help if the problem persists even after replacement.

Malfunctioning Door Switch Causing Humming of Dishwasher

The door switch malfunctioning can shut down the dishwasher and all of its functioning. The normal function of the door switch is to turn off the dishwasher in case of any damage. It also prevents dishwashers from starting the wash cycle if the door is kept open.


It is very easy to check the functioning of a door switch. Look for any visible damage at first. Then use a multimeter to check for the continuity of the circuit. If any of these two is breached, the door switch will malfunction, and the wash cycle will not start.

Its repair is also very easy. You can easily find a replacement on Amazon or you can contact the manufacturer. You can the door switch yourself by following these instructions:

∙         Make sure that the power is turned off and the dishwasher is unplugged

∙         Open the inside panel to gain access to the switch

∙         Disconnect the wires and demount the screws. Remove the damaged door switch

∙         Install the new switch by reversing the whole process

Final verdict

The humming sound of a dishwasher indicates normal functioning. The partial filling is one of the main causes of humming sound without proper functioning. Insufficient filling of the dishwasher tub results from lime formation in the inlet valve, door switch damage, and float switch damage.

The best method to combat these problems is to replace the nonfunctional parts. Changing your water source also proves beneficial in preventing the blockage of the inlet valve.

You can replace most of these parts yourselves. Just follow the simple steps and wear safety equipment first. Professional help is required in any complex case or if the problems persist after replacement.

I hope I was able to answer all your queries regarding dishwasher humming but not working. If you still have any questions, feel free to ask in the comment section.