Motion detectors sense the slight changes in temperature caused by objects as they pass though the light's motion detector range. Motion lighting can create a sense of security around your home if they work properly. There are several reasons why a motion light would stay on and not operate correctly. Doing a little troubleshooting can help you find the cause and reset the light.
Move the motion sensor to a position away from an exterior air conditioning unit, a dryer vent or a heat vent. The heat from these objects could trigger the motion detector and cause the light to remain on.
Position the sensor away from objects such as trees and shrubs. The wind blowing though the leaves can cause the detector to sense motion, keeping the light on. Make sure the motion light is mounted to a sturdy service. A surface that moves can create false triggers and turn on the light. Verify that the sensor isn't pointed toward the road. Passing cars can cause the light to come on and stay on.
Check the time switch to confirm it isn't set in "Test" mode. If set in "Test" mode, move the switch to a pre-determined time setting. The "Test" mode could cause the light to come on and remain on.
Reset the light to make sure it isn't set to manual operation. Turn off the light switch that operates the motion light. Leave the light switch off for one to two seconds. Turn the light switch back on to reset the motion light to automatic.