When i was a kid the one in front of my house flicked on and off all night. I played in the street in front of house as a kid. I would be riding my skateboard and I hear the light make a buzzing noise then it would kick off for a few minutes. Then it cranked itself back up and stayed on another half hour or so. My guess was it overheated and has a breaker or something that kicked on and off. I hated that light so I shot it out with a b.b. gun. It got replaced and worked fine after that. I have heat lights in my bathroom ceiling that do the same thing. Burn for a while, kick off for a few, burn some more.