photocell manual override

If it's a totally solid state unit, it probably means the 'switch' has failed. These tend to fail in an on condition.

On Thu, 25 Nov 2004 09:07:07 +0000, Ben strung together this:

Usually if a device has a manual override built in turning it off then on quickly will turn it on permanently. To turn it off, (if it is this that's the problem), then you'll need to turn it off for a good few seconds before turning it back on. Chances the photocell is knackered though, but as they're only about a tenner to replace it's not the end of the world.

I've tried leaving it off for several hours and that didn't work.

Sounds like it. I think I'll fit a separate photocell - that way, when I come to replace the light with a more decorative one, I won't need to choose another one with a photocell built in.

Take it indoors and dry it out with a hairdryer and see if that works. If not chuck it.

Is this a dusk til' dawn light? One which only comes on when it get dark enough? Or is it a passive infra red (PIR) detector that senses movement and switches on the light?

If it's really a dusk til' dawn light, then try cleaning the lens of the photo detector or looking inside to see that the connections haven't come loose and are touching over the terminals, or that water isn't shorting them across. If it's a PIR, then also look inside for loose connections or moisture that is touching over the wrong terminals. But a PIR that is stuck in the "on" position is usually beyond repair and, so, will need replaced.