A garbage disposal that stops and hums is usually stuck on something small. A spoon, a bone, or a fibrous peel can wedge the flywheel. Clearing that jam is a task most households can do themselves, provided the power is off first. Other work on the unit is not a self-service task, and knowing where the line falls keeps the job safe and keeps the paperwork clean.
Start with the power off
Turn off the power at the breaker that feeds the disposal before you reach toward the chamber. Some disposals also have a switch under the sink, but the breaker is the step that makes the work safe. Keep the breaker off until you finish.
Clear the jam by hand
Look into the chamber with a flashlight. Remove anything visible with tongs or pliers, never with your hand. Most units have a hex socket on the underside of the motor. Insert the hex wrench that came with the unit, or a matching one, and turn it back and forth to free the flywheel. Once it turns freely, remove the wrench, check the chamber again, and then press the reset button on the underside. Restore the breaker and run cold water before you test the unit briefly.
Know when to stop
If the flywheel will not turn, if the unit hums after the reset, or if you see scorching or a burning smell, stop and leave it off. Do not attempt to reach the wiring or open the motor housing. Those steps belong to a licensed electrician.
Hand these to a professional
Hire a licensed electrician for any wiring change, any replacement of the switch or the cord, and any problem with the circuit that feeds the unit. Hire a plumber for drain tie-in work, sink flange changes, or leaks at the mounting. Hire a technician for a unit that will not run after a clear and reset.
Check the paper before you clear
Read the warranty for the disposal. Some warranties state which self-service steps are allowed and which must be done by an authorized service provider. Keep the install record with the warranty so the answer is at hand.
Plan the replacement window
If the unit is repeatedly jamming or the motor is weakening, read the Garbage Disposal guide to see where its install year places it on the typical service life. A repair is one decision. A replacement planned around the install year is another, and it is often the easier one to schedule.