Some electrical problems can be attributed to human error while other problems are caused by faulty wiring or electrical device failure. There is usually a logical reason for an electrical failure and you can often locate the cause through process of elimination. If you need to troubleshoot a ceiling light that is not working, some basic knowledge of an electrical tester will help. While troubleshooting any electrical device, the electricity stays on. Caution is required.
Check your home's circuit breaker at the main electrical panel. Make sure the breaker that supplies electricity to the ceiling light circuit is on. If the breaker is on, move to the next step.
Remove the ceiling light cover or shade to gain access to the light bulb. Remove the light bulb by turning counterclockwise. Check the filament inside the bulb to verify that the filament is still intact. If the filament is broken or burnt, replace the light bulb. If the light bulb will still not light, move to the next step.
Test the socket of the light fixture. Use the two prong electrical tester and insert one prong to the socket touching the contact at the centre of the socket. Touch the other prong to the side of the socket or any other metal on the ceiling light. If the tester does not light, move to the next step.
Remove the ceiling light to expose the wiring in it's electrical box. Check for any loose wiring. Confirm that the black wires and the white wires in the electrical box are secure. Test for electrical power by placing one prong of the tester into the wire connector that holds the black wires together and touch the other prong to any metal on the electrical box. If the tester lights up, your socket may be damaged and need replacement. If the tester does not light up, move to the next step.
Remove the cover to the light switch that controls the ceiling light. Confirm that wires are connected securely to the switch. Inside the electrical box, confirm that the white wires are connected securely together with a wire connector and that the bare copper wires are also secured together. With the light switch in the on position, touch one probe of the electrical tester to the screw on the right side of the switch, where the black wire from the ceiling light is connected. Touch the other probe to any metal on the electrical switch box. If the tester does not light up, move to the next step.
Touch one prong to the black wire on the right side of the switch. This wire supplies electricity to the switch. Touch the other prong to any metal on the switch box. If the tester lights up, the light switch could be damaged and will need to be replaced.
You will be working with live electricity so make sure your hands are dry and you are standing on dry ground or a piece of wood.