How to test and replace your garbage disposal motor

Is your garbage disposal acting up—making weird noises or refusing to turn on? Before you toss it out and buy a new one, you might be able to fix it yourself. The motor’s often the issue, and with a few simple steps, you can test and replace it to get your kitchen back in action.

The information in this article may not apply to your specific appliance model. We recommend consulting your manufacturer’s documentation or contact us with any questions.

Safety precautions

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind: 

• Always power off and unplug your appliance or switch off the circuit breaker before attempting any maintenance or replacement work. This keeps you safe by preventing any risk of injury from electric shock.
• Wear insulated work gloves to protect your hands from sharp metal parts, pinching hazards and debris.
• Take your time and don’t rush while working to prevent accidents and personal injuries.
• Work in a well-lit area so you can clearly see and access the interior parts.
• Clear your workspace of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with bare wet hands. Make sure the work area is completely dry.
• Check your user manual to see if there are specific installation or safety instructions for your part or appliance. 
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause injury.
• Wear safety glasses when working with chemicals, dust or cleaning large debris to prevent injury. 
• If the appliance has recently been used, give it plenty of time for any heating parts to cool down before working on it. 
• Take pictures or make a note of wiring terminals or other connections before disconnecting to prevent any problems with reassembly.
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.

Troubleshooting steps

1. Check the power supply

First off, make sure your garbage disposal’s properly connected:

1. Check the outlet: See that the disposal’s plugged in securely.
2. Peek at the circuit breaker: Go to your home’s electrical panel and see if the circuit breaker for the disposal has tripped. If it has, flip it back on.

If everything looks fine but the disposal isn’t working, test the outlet:

1. Use a voltage tester: A voltage tester or multimeter will tell you if power’s reaching the disposal outlet.
2. How to test: Set the multimeter to AC voltage. Stick the probes into the outlet slots. A reading around 120 volts means the outlet’s good.

No multimeter? Don’t have one? You can pick one up at a hardware store—they’re handy for lots of DIY projects.

2. Reset the disposal

Your garbage disposal has a built-in overload protector:

1. Find the reset button: Usually red and located at the bottom or side of the unit.
2. Press reset: Push it firmly until it clicks. That resets the internal breaker.

After resetting, turn the power back on and test the disposal:

1. Listen up: If you hear a humming but the blades aren’t spinning, the motor might be jammed or shot.
2. Silence: If there’s no noise at all, it could be an electrical issue or a burned-out motor.

3. Free the jam

Jammed motors are a common problem:

1. Find the hex hole: Underneath the disposal, look for a hex-shaped hole in the center.
2. Insert the wrench: Use a 1/4-inch Allen wrench (often comes with the disposal) and stick it into the hole.
3. Work it: Turn the wrench back and forth to free up any obstructions. This manually moves the impeller plate.

If your disposal doesn’t have a hex hole:

1. Use a wooden tool: Stick a wooden spoon or dowel through the sink drain and try to rotate the blades manually.
2. Keep hands out: Never put your hand inside the disposal—for obvious reasons.

4. Inspect and clean

Things stuck in the disposal can cause it to stop working:

1. Take a look: Use a flashlight to peer inside for any visible blockages.
2. Remove debris: Use needle-nose pliers or tongs to fish out any foreign objects like bones, utensils, or fibrous food waste.

5. Test the motor

If it’s still not working, test the motor’s resistance:

1. Access the wiring: Unplug the disposal and remove the electrical cover plate underneath.
2. Set up the multimeter: Switch it to the ohms (resistance) setting.
3. Test the windings: Place the probes on the motor terminals to measure resistance.
4. Read the results: Compare what you get to the manufacturer’s specs. If it’s way off, the motor’s probably bad and needs replacing.

If you’re not sure how to use a multimeter or read the measurements, check out our repair help section for some handy guides.

Replace the motor

1. Unplug the disposal: Ensure the garbage disposal is unplugged from the electrical outlet to avoid any electrical hazards.
2. Disconnect the drain and power connections: Use a wrench or pliers to disconnect the drain pipe and the power supply cable from the disposal. Take note of how everything is connected for reassembly.
3. Remove the disposal unit: Unscrew the mounting bolts holding the disposal to the sink. You may need a screwdriver or wrench for this. Carefully remove the disposal from under the sink.
4. Disassemble the disposal: Take apart the disposal to access the motor. This typically involves removing screws that secure the motor housing. Use a screwdriver to carefully open up the unit.
5. Replace the motor: Remove the old motor by unscrewing any bolts or screws securing it in place. Install the new motor in the same position, ensuring all connections match the old setup.
6. Reassemble the disposal: Reassemble the disposal by reversing the disassembly process. Make sure all screws and bolts are tightened securely.
7. Reconnect the disposal: Reconnect the drain pipe and the electrical connections. Ensure that everything is properly secured and reconnected.
8. Test the disposal: Plug the disposal back in and test it to ensure it operates correctly.

Install a new garbage disposal 

It’s often easier and more cost-effective to replace the entire disposal unit rather than just the motor. In some cases, the motor is not sold as a separate part and you would need to replace the entire disposal. If the garbage disposal is old or the motor is severely damaged, replacing the whole unit might be the best option.

1. Turn off power: Double-check that the power’s off at the circuit breaker.
2. Disconnect wires: Remove the electrical cover plate and disconnect the wiring.
3. Loosen mounting bracket: Use a screwdriver to loosen the screws connecting the disposal to the sink.
4. Detach drain lines: Disconnect the dishwasher hose and the drain pipe from the disposal.
5. Remove the disposal: Carefully twist and lower the unit from the sink mount.
6. Prep the new disposal: Follow the manufacturer’s instructions to get it ready.
7. Connect wiring: Attach the wires to the new disposal, matching the colors.
8. Mount to sink: Align and secure it to the sink mount using the ring and screws.
9. Reconnect drain lines: Hook up the dishwasher hose and drain pipe.
10. Restore power: Turn the power back on at the breaker.
11. Test it out: Run some water and turn on the disposal to make sure it’s working.

Wrapping up

By following these steps, you can test and replace your garbage disposal motor yourself, saving some cash and getting things back to normal. Regular maintenance helps extend your disposal’s life and keeps your kitchen running smoothly. For more tips, visit our repair help section.

At AppliancePartsPros.com, we’re here to back you up with quality parts and expert advice for your DIY repairs. If you need help or have questions about your garbage disposal, don’t hesitate to reach out. Join our community of DIY enthusiasts on Facebook and Twitter for tips, updates, and support. We’re always ready to help you keep your appliances in top shape.