How To Repair a Garbage Disposal

A garbage disposal is one of the most used appliances in the kitchen and makes cleaning up after meals so much easier by grinding up food scraps before sending them down the sink drain opening. But a jammed disposal can cause food particles to quickly clog sinks that can then lead to unpleasant odors and backed-up water. 

Thankfully, many common garbage disposal issues can be fixed with simple repairs. Read on for more information about how to troubleshoot and fix your garbage disposal system.

Causes of a faulty garbage disposal

Start switch issues in batch feed disposals

Many garbage disposals use a batch feed system, which relies on a stopper to activate the start switch. Start switches are often designed for quick connection, using either push-fit wire terminals or screw clamps. This switch triggers the disposal’s grind motor when the stopper is inserted, and it can fail or malfunction over time. 

If your batch feed disposal was working normally but suddenly stopped, the start switch should be the first thing to check. Start switches can fail due to normal wear and tear, food waste buildup, or defective electrical components.

1. Turn off the disposal’s electrical supply at the breaker.
2. Visually inspect the start switch for any blockages.
3. Scrape off any accumulated gunk with a toothbrush or small probe.
4. Use a multimeter device to test for electrical continuity through the switch. Place one probe on each terminal and see if the current flows freely through it. If the start switch fails the continuity test, it will need to be replaced.
5. If the start switch needs to be replaced, find the manufacturer name and model number on the old switch. These are usually printed somewhere on the housing. Head over to AppliancePartsPros.com or call us at to order the correct replacement switch for your disposal’s make and model. Most orders are expected to arrive in as little as 2-3 business days.
6. Once you have a new start switch, turn off the disposal’s electrical supply at the breaker before replacing.

Faulty wall switch connections

Some garbage disposals are wired directly to a wall switch instead of using a batch feed start switch. This wall switch cuts power to the disposal to turn it on and off. If the wall switch connection is broken, it will disable the disposal entirely.

1. First, you need to check for a tripped circuit breaker or blown fuse. Restore power at the breaker or replace the fuse if they are faulty. Make sure to take proper safety precautions when working with household electrical wiring.
2. Use a multimeter to check for continuity through the wall switch itself. No continuity means the switch has failed internally. The switch will need to be replaced in this case.
3. Inspect the wiring connections behind the wall switch. Loose wire nuts or terminal screws can interrupt the electrical supply. Secure any loose wiring and restore solid switch connections.

Faulty wall switch wiring should be repaired by qualified electricians for safety. But properly restoring connections is often an easy fix to get disposals working again.

Worn-out motor that just hums

The electric motor that powers the grinding plate is the true workhorse of a garbage disposal. These motors operate whenever the disposal is turned on, grinding up wet food waste. Years of continual use can eventually wear them out.

Listen closely to your malfunctioning disposal. If the motor hums but fails to rotate, this indicates a worn-out motor. Unfortunately, these grind motors cannot be repaired or lubricated when worn. The entire disposal unit typically needs to be replaced when the motor fails.

Installing a new garbage disposal is the only solution for a failed grind motor. On the bright side, new disposals often have better motors and technology than older models. You may find that a fresh disposal grinds more efficiently and quietly than your previous one.

When purchasing a replacement, try to match the existing disposal’s horsepower rating and dimensions. This makes installation simpler. Improper motor size or fit issues can lead to problems down the road.

Jammed grinding chambers

Garbage disposals have a safety mechanism that causes them to shut off when the grinding chamber becomes jammed. This protects the motor from damage. Heavy food waste or foreign objects can sometimes cause jams and prevent things from draining smoothly.

Start troubleshooting a jammed garbage disposal by pushing the reset button on the disposal’s housing. This button temporarily disengages the safety switch. Try turning on the disposal after resetting it. If you push the reset button and it continues to trip, unplug the disposal and inspect the grinding chamber.

Use an Allen wrench or broom handle to manually turn the grinding plate. This should help dislodge any stuck food waste or objects. Be sure to avoid reaching inside the chamber with your hands. Serious lacerations can occur.

Finally, test your disposal’s safety switch using a multimeter. If the switch shows poor continuity after resetting, it may need replacement. Safety switch failures are common when disposals frequently jam up.

Preventing future jams helps avoid tripped safety switches. Run plenty of cold water when using your disposal and avoid grinding extremely dense or fibrous waste. Proper maintenance of the sink drain opening can also keep food particles from accumulating.

More information

Thank you for reading! We hope you found this information useful to get your garbage disposal working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our thousands of free videos and troubleshooting guides available. If you need replacement parts or some extra help, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, order parts, read our DIY blog and more.

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