Dusk till dawn light not working anymore

[coldasfcuk]

We installed a dusk till dawn light about 1 year and a half ago and it has been working great up till now.

Now when we turn it on, it just flickers for 30 seconds and then goes out and it won't come back on. Or it may not even come on at all. It seems really odd. The fact that its coming on tells me the bulb is ok and the fuse is ok, well hopefully.

I took it apart today and checked all the wiring and that seems fine. Changed the light bulb and fuse anyway and still no joy.

The only thing I can see, is in the sensor there are some little condensation droplets. Could this be the cause?

The light is a bog standard B&Q jobbie we got for about £40 or £50.

Any ideas?

 

[JohnD]

it flickers? does it have a fluorescent tube, a CFL, or a filament bulb?

A replacement need not cost so much.

http://www.screwfix.com/app/sfd/cat/cat.jsp?cId=101031&ts=80686

 

[coldasfcuk]

Its a standard filament light bulb.

As for the cost, that was just sort of a guesstimate.

 

[breezer]

i would recomend getting one of each.

light sensor and lamp, better idea, more reliable

 

[chadtheanimal]

Could it possible be a metal halide lamp?

The following is from wikipedia and sounds similar to what you describe.
At the end of life, metal halide lamps exhibit a phenomenon known as cycling. These lamps can be started at a relatively low voltage but as they heat up during operation, the internal gas pressure within the arc tube rises and more and more voltage is required to maintain the arc discharge. As a lamp gets older, the maintaining voltage for the arc eventually rises to exceed the voltage provided by the electrical ballast. As the lamp heats to this point, the arc fails and the lamp goes out. Eventually, with the arc extinguished, the lamp cools down again, the gas pressure in the arc tube is reduced, and the ballast can once again cause the arc to strike. The effect of this is that the lamp glows for a while and then goes out, repeatedly.