Does your dishwasher seem strangely silent after filling with water? Or are you just hearing a low hum? That could mean the appliance’s circulation pump motor has burned out. If you find water pooling across the bottom of the tub area or leaking onto the floor when you open the dishwasher door, then the drain pump motor could be malfunctioning.
Both of these pump motors are critical to dishwasher operation… and both of them can be replaced with new ones to fix the appliance. Is replacing a dishwasher pump motor strictly a job for the professionals? Not if you’re a patient do-it-yourselfer. Once you understand the procedure, installing a new circulation or drain pump might be easier than you think.
How can I tell if a dishwasher pump motor is defective?
Diagnosing the cause of pump failure is not too much of a mystery, provided you know how the pumps do what they do. Circulation pump motors use an impeller to force water through the dishwasher’s wash arms to thoroughly clean the dishware during multiple wash and rinse cycles. Drain pump motors use an impeller to force the water through a drain hose to a garbage disposer or sink drain pipe during multiple drain cycles. Keep in mind that some dishwasher models will use only one pump motor to both circulate and drain the water.
You should eliminate all other possible causes for why the dishwasher may not be circulating water or draining it. This means making sure hoses or wash arms are unobstructed and free of damage, check valves or check balls are working properly, and, if applicable to your model, the drain solenoid valve is functional. Evidence like excessive water pooling in the sump area or the lack of any sound when the appliance should be in a wash cycle will also help narrow the source of the problem down to the pump motors.
The pump motors can fail both electrically and mechanically. You can use a multimeter to help determine if the pump has failed electrically by testing for electrical continuity, a continuous electrical path present in the motor. If the motor tests “negative” for continuity, you know the component is defective. If the motor tests “positive” for continuity, there could still be a mechanical failure such as a broken or obstructed impeller or seized motor bearings. If the problem is with the bearings, repairing means installing a new pump motor. However, you may be able to just clear the obstruction preventing the impeller from spinning to solve your problem. Even if the impeller is broken, you might be able to replace it independently of the pump motor, depending on the model.
What’s it going to take to replace a pump motor?
The procedure to replace a dishwasher pump motor will differ from model to model, but there are still some basic steps that are going to be common across all of them. On some models, replacing a drain pump will only require you to remove the lower access panel or panels, reach under the dishwasher, disconnect the wire harness from the pump, then depress a retaining tab and rotate the old pump counter-clockwise to release it from the sump housing. To install the new pump, insert it into the pump housing and rotate it clockwise to lock it into place. Connect the wire harness, then replace the access panel or panels. Of course, before you attempt this, you should shut off the power to the appliance.
Most pump replacements, however, are going to be more involved and the majority of them require you to fully uninstall the dishwasher.
Uninstalling the dishwasher
Again, the process of uninstalling a dishwasher will vary depending on the model, but you can use these steps as a general guide:
- Shut off the power supply to the dishwasher to prevent shock, as well as the water supply.
- Remove the screws or fasteners to detach the dishwasher’s lower access panel or panels.
- Use pliers to unthread the water supply line or elbow fitting from the water supply valve – be prepared for some water to spill out.
- Remove the junction box cover and separate the power wires by untwisting the wire nuts. Release the grounding wire as well.
- Unthread the power cable strain relief nut so you can detach the cable from the junction box.
- Detach the drain hose from the sink drain or garbage disposer.
- Unthread the screws securing the dishwasher’s mounting brackets to the cabinet, countertop, or floor.
- To move the dishwasher, you may need to adjust the legs to lower the appliance.
- Gently pull the dishwasher away from the cabinet and countertop.
Replacing the circulation pump or drain pump motor
With the dishwasher fully uninstalled, tip the appliance back and rest the rear panel on a towel or blanket. This should give you full access to the pump motor assemblies attached to the bottom of the tub (where both the drain pump motor and circulation pump motor are usually found). Be aware, some models may require you to remove an access panel or plate to reach these components. You will usually be able to replace the circulation pump motor and the drain pump motor is a similar way:
- Disconnect the pump motor power wires and grounding wire(s) as applicable.
- Detach any hoses from the pump motor ports.
- Depress the retaining tab to rotate the pump free, unhook the pump from the base, or unthread the mounting screw or screws securing a mounting bracket, retainers, and/or the pump to fully remove the component.
- When installing the new pump motor, you may want to apply some lubrication to the gaskets. You may also need to confirm that the gaskets or isolators are properly seated in the new pump or, if necessary, transfer the gaskets or isolators from the old component to the new one.
- Secure the new pump motor to the dishwasher base (realigning the mounting bracket or retainers, rethreading the mounting screws, etc.).
- Attach the hoses to the ports, if applicable, and secure with the appropriate clamps.
- Connect the power wires and grounding wire(s) as applicable.
Be aware, for some circulation pump motor replacements, you will need to uninstall the drain pump motor first (then reinstall the drain pump motor afterwards). You may also need to fully uninstall dishracks, wash arms and supports, water guides, and filter assemblies before you can replace the pump and motor assembly (this is when the pump motor must be lifted out of the sump housing from the inside of the tub and installed the same way).
Reinstalling the dishwasher
Once the new pump motor has been installed, you will need to reinstall the dishwasher:
- Confirm the end of the drain hose is accessible through the hole in the cabinet wall then slide the dishwasher back into the cabinet.
- Adjust the legs if necessary.
- Rethread the screws to secure the mounting brackets to the cabinet, countertop, or floor.
- Reattach the drain hose to the sink drain or garbage disposer making sure the hose is elevated above its connection point.
- Reinsert the power cable strain relief in the junction box and secure with the nut.
- Secure the grounding wire then join the black wires together and the white wires together using the wire nuts.
- Replace the junction box cover.
- Reattach the water supply line or fitting to the water inlet valve port.
- Realign the lower access panel or panels, using the screws or fasteners to secure.
- With the reinstallation complete, turn the water supply and power supply back on.
Find detailed repair procedures and the right parts with Repair Clinic
While the procedure shown above is very general, Repair Clinic.com has dozens of precise step-by-step videos and guides showing how to replace both circulation pump motors and drain pump motors on popular dishwasher models from brands like KitchenAid, Kenmore, Maytag, Samsung, GE, Electrolux, Frigidaire, LG, and Whirlpool. Type the full model number of your dishwasher into the Repair Clinic website search bar to see what info is available. By entering the model number, you’ll also get a full list of replacement parts compatible with your specific dishwasher. Need to identify the right pump motor for your unit? Narrow the list down by selecting “Motor” or “Pump” using the “Part Category” filter then choose the appropriate selection from the “Part Title” filter (Examples: “Pump and Motor Assembly” / “Drain Pump” / “Circulation and Drain Pump Motor”).