Lighting, Light Fixtures, Ceiling and Exhaust Fans - Motion detector light keeps going on & off

I live in Phoenix AZ, and have installed a motion detector in the porch light circuit at the fixture. I've installed a number of these light sensors with good results, but none in AZ where it is HOT. The side edge of the sensor is 2-3 inches from the garage wall, and parallel to same. This is the first time I've installed a sensor so close to a wall. The light cycles on and off repeatedly. Is it possible the sensor is picking up heat from the garage wall?

Does the fixture have a photo sensor in addition to the motion sensor? Does the fixture have a sensitivity control?

Motion detectors are sensitive to the hot and cold. The plastic that the sensor looks through, will move with the heat,at night, when you need it to work. Its cold there at night,right? The heat from the wall and the cold of the night air will keep the eye seeing the plastic cover move. Try putting a heat shield of some kind between the light and the wall.

Travis

Its cold there at night,right?I see you've never been to Phoenix in August.

i have an odd approach to it i have installed many of them and they are sometimes finicky but maybe it is the reflection of the wall or something i havent exactly come across your issue but i dont know try painting it a dull color near it so it doesnt reflect to the sensor so easily if there is in fact something doing that or possibly from all the hot/cold you have cold have moisture inside on the plastic shield and as it drips it could pick it up. but then again it is az and i dont know how much moisture there actually is. or it can be just a faulty sensor givin you looked at the sensitivity controls and such like mr nelson said

I see you've never been to Phoenix in August.

Nope, never been there. But would like to go sometime.
I just meant the contrast between night and day.

I think Chewy is on the right track. The reflection of the light on the light surface is reflecting back into the photocell, telling the unit is is daytime. When it goes off, the sensor is telling it that it is nighttime, causing the erratic action.

Thanks all,

Read the replies. The detector does have a photocell and sensitivity control. In the daytime the temp at the light hits 110-120 and at night it's 100-110. The humidity is really low, so moisture isn't an issue. I'm going to play around with positioning (very limited amount of side to side swivel) and sensitivity. I suspect radiated heat is being picked up and turning the unit on.

I think the explanation is simpler. I think reflected light is triggering the photo sensor. Put black tape over the photo sensor as an experiment.

Well it's been quite a while since my last post. As directed by several persons responding to my first post, I have done two things.

1) Limit the ability of the heat sensor to detect heat from the nearby wall. The sensor still exhibited the undesired off/on/off/on cycle repeatedly after sundown.

2) Blind the photocell. This stopped the off/on cycles.

I used duct tape to accomplish both objectives and will replace the tape with something more permanent soon.

My thanks to all!!!
Dashadeaux

As mentioned by another poster once, here in the South, there is nothing more permanent than duct tape, is there?