If I were doing it myself I would check if there was power going to the fitting. If there is and depending on how much the fitting cost I would probably assume that it's broken, bin it off and buy a new one.
If it's a more expensive fitting there could be adjustment controls for the light intensity (so it doesn't come on during the day) and amount of time the light stays on for. If it's got these, try having a play around with them.
Adam
January 2009
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