How to Fix a Buzzing Dimmer Switch

1. Turn off Switch and Remove Bulb

   Turn off the power to the light fixture at the switch. Safely access the light fixture on a step ladder. Remove the lightbulb.
   

2. Change Bulb for Lower Wattage Bulb

   Replace the bulb with a lower wattage bulb to place less demand on the dimmer switch.

   Calculate the number of light fixtures served by the dimmer switch and multiply that number by the wattage per bulb. Multiply that by 1.25 to arrive at the correct dimmer wattage choice.

   Tip

   For example, if your dimmer rated at 375 watts currently serves three 100-watt bulbs, try changing them out for 75-watt bulbs.

3. Change Bulb for Rough Service Bulb

   If stepping down the wattage doesn't work, try changing out the bulbs for rough service bulbs.

   Rough service lightbulbs are designed to be used in garages, shops, and other areas of heavy vibration. Rough service bulbs have more wire within the glass to help protect the filament.

4. Shut Down Power at Circuit Breaker

   If the previous steps don't help, try changing out the dimmer switch. Shut off the power to the dimmer switch by shutting off the circuit breaker at the electric service panel.
   

5. Access Dimmer Switch

   With the flat-head screwdriver, remove the faceplate on the dimmer switch box. Before touching anything in the box, run the voltage tester against the dimmer switch's terminals. Make sure that you first verify that the voltage tester is working by trying it out on a known working outlet.

   Remove the switch mounting screws by running the cordless drill with a driver bit counter-clockwise. Extract the switch from the box by holding it by the mounting straps. With full access to all of the attached wires, once again test the wires with the voltage tester. If there is no voltage, proceed.

6. Replace Dimmer Switch

   Detach all of the wires from the dimmer switch. With the wire stripper, snip off any mangled wire ends. Re-strip the wire coatings to expose bare wire. If necessary, rip back any cable sheathing to expose more wire.

   Two hot or live wires (usually black) enter the box. Attach one of those hot wires to the black wire on the dimmer switch. Attach the second hot wire in the box to the dimmer switch's other hot lead (usually black or red). Attach the green wire on the dimmer switch to the bare copper (sometimes green) ground wire that enters the box.

   Double-check any wires attached with wire nuts. No bare copper wire should be exposed. If so, twist off the wire nut, snip a tiny bit off of the end of the wires, then attach the wire nut again.

   Attach the dimmer switch to the box with the mounting screws. Attach the faceplate with the flat-head screws. Turn on the circuit breaker and test the light.
   

When to Call a Professional

When the dimmer switch itself is buzzing and there is also a crackling sound or a burning smell, this may indicate electrical arcing, a dangerous condition. Shut down the current at the service panel by turning off the circuit breaker and call an electrician.