Security lights are automated lights that are either motion-controlled or light sensitive. The lights will turn on in response to movement or when it gets dark and triggers the light sensor. If a security light is not working properly, it could be an issue with the bulb, the power supply or the sensor itself. Repairing an outdoor security light can usually be done quickly so long as the light has not shorted out entirely.
Ensure the light is receiving power. If the light is hooked up to a switch, make sure the switch is on and that no one is turning the switch off accidentally. If the light is not getting power, inspect the wires for any signs of damage, make sure they are connected to the light and the power supply and then check the breaker to make sure it is turned on. If the light is battery powered, try changing the battery.
Dust off the light's sensors with a damp rag. You may need a ladder to reach the light. Dust and debris can cover exterior lighting and cause the sensors to malfunction. Keeping the sensors clean is a good way to make sure your light always functions optimally.
Inspect the setting on your light. Light-sensitive security lighting will have a switch that determines how low the natural light needs to be before it turns on and motion-sensor lights have a switch as well determining how sensitive the light is to movement. The switches can be adjusted either by sliding them back and forth between different settings or by turning a screw with a screwdriver, depending on your individual model.
Aim your lights to make sure they are covering the area you wish them to cover. If a motion sensor light is aimed too high, a moving tree branch could potentially activate it. Have someone else stand outside with you both at night and during the day while you adjust the height and the sensors of the lights to make sure they come on when you want them too and not when they are not needed.
If your lights still are not working properly, they may require professional service or replacement.