How to Fix a Light Switch That Won't Work

Most non-working light switches are caused by loose wire connections, a faulty switch, or a tripped breaker. Start by checking the circuit breaker, then test and replace the switch if needed.

  1. Kill the Power First. Locate your electrical panel and flip the breaker that controls the problematic switch to the OFF position. Test the switch to confirm power is off by attempting to turn the lights on. If you're unsure which breaker controls the switch, turn off the main breaker temporarily while you work.
  2. Expose the Switch. Use a screwdriver to remove the two screws holding the switch plate cover. Set the screws aside in a small bowl so you don't lose them. Pull the cover plate away from the wall to expose the switch.
  3. Pull Out the Switch. Unscrew the two screws at the top and bottom of the switch that secure it to the electrical box. Carefully pull the switch out of the box, bringing the attached wires with it. Don't yank on the wires - pull gently by the switch body.
  4. Inspect Every Connection. Examine where the wires connect to the switch. Look for loose, burned, or corroded connections. If you see loose wire nuts or wires that have pulled away from terminals, this is likely your problem. Tighten any loose connections with wire nuts or reconnect wires to their proper terminals.
  5. Verify Switch Function. Set your multimeter to continuity mode. Touch the probes to the two brass terminals on the switch while flipping it on and off. You should hear a beep when the switch is ON and silence when it's OFF. If the switch doesn't show continuity in the ON position, it's defective and needs replacement.
  6. Wire the New Switch. If the switch failed the continuity test, buy a matching replacement from any hardware store. Connect the wires to the new switch exactly as they were on the old one - typically black (hot) wires to brass terminals and white (neutral) to silver terminals. If there's a green or bare copper wire, connect it to the green grounding screw.
  7. Restore Power and Verify. Push the switch back into the electrical box and secure it with the mounting screws. Replace the switch plate cover. Turn the circuit breaker back on and test the switch. The lights should now work properly.