A ceiling light flickers due to different factors. When troubleshooting a flickering light, start with the bulb and work your way backwards. The issue is perhaps a simple worn-out bulb or loose wires resulting in a fire hazard. When you notice a light flickering, take time to flesh out the reason before the issue becomes a larger, more dangerous issue.
Turn off the light switch, remove the cover from the light fixture and replace the light bulb with a new one. Turn on the light fixture and wait a few minutes. If the light does not flicker, reinstall the cover because you resolved the issue. If it still flickers, move to the next step.
Turn off the light switch, locate the breaker for the room's electrical circuit and turn it off. Turn on the light switch to ensure the light does not turn on. If it still turns on, you turned off the wrong breaker.
Remove the light bulb from the fixture, locate the screws that hold the fixture onto the ceiling and remove with a screwdriver.
Pull the fixture away from the ceiling to expose the wire connections. Carefully inspect each wire for a break or missing insulation.
Remove the electrical tape (if present) and the wire nuts from each wire connection.
Twist the wires together to ensure they have a proper connection. Place the wire nut over each connection and twist until the nut is tight on the wires. Wrap each wire nut individually with electrical tape to prevent the nut from working loose over time.
Secure the fixture back to the ceiling with the screws and screwdriver. Place the light bulb back into the fixture, turn on the breaker and test the light. If it no longer flickers, you had a loose connection. If it still flickers, move to the next step.
Turn off the breaker, then remove the cover plate from the electrical switch that controls the light. Remove the screws that hold the light switch into the electrical box.
Pull the switch out of the box to expose the wiring. Check each wire carefully for any breaks or missing insulation. Check that each wire in the box has a secure connection to the terminals on the switch. Tighten each terminal with the screwdriver.
Place the switch back into the box and secure it, Place the cover over the switch, turn on the breaker and test the light. If it works, the short was at the switch. If it still flickers, move to the next step.
Turn off the breaker, remove the light switch cover and light switch. Remove the wires from the light switch by loosening the terminals. Make sure you remember all wire placements. Connect the wires to a new switch, mount the switch back into the box and reinstall the cover plate. Turn on the breaker and test the light. If the light still flickers, move to the next step.
Turn off the breaker again. Remove the light bulb from the fixture, remove the fixture from the ceiling, then remove the wire nuts and disconnect the wires.
Wire a new fixture. Secure the green wires coming from the ceiling to the green grounding screw. Secure the white wires together and secure the black wires together. Cover each wire with a wire nut and electrical tape.
Secure the fixture to the ceiling, install a bulb, then turn on the breaker. If the light still flickers, consult a licensed electrician because you likely have an issue with your breaker box or with the wiring inside the wall.
If you encounter broken wires or missing insulation by the fixture or the switch, cut the wire behind the break if you can easily stretch it to the fixture or switch. Once cut, strip the end of the wire, then reattach the wire to the fixture or switch. If you cannot stretch the wire, consult a licensed electrician to have the wire removed from the wall and replaced with a new one unless you are comfortable with that process.