The sensing unit on the fixture is thinking that it is night
time. If your fixture has a switch before the light, that has to be
left on for the sensor to work, try the following. Turn the fixture
off with the switch and leave it off for about ten minutes. Turn
the switch back on and the fixture will turn on. If the sensor
circuitry is working the fixture will turn off after your "delay
on" setting is reached.
If there is no switch before the fixture check to see if the
sensor has been covered, fooling the sensor into thinking it is
night time. If it is a hollow tube type sensor, sometimes hornets
will lay an egg in there and cover the sensor with a mud patch.
As a last resort change the sensitivity control so that is
senses daylight sooner, allowing the sensor to shut off earlier. If
none of the above work its time to buy a new sensor. These can be
bought individually and installed into the old fixture.
