I installed a motion sensor in my laundry room around 8 months ago to control both the single light in the laundry room and the lights in the garage. It worked great for a few months, but at some point (since it's near the dryer), the shield that covers the eye vanished. I suspect it fell out, but I'm not sure when.
Now, when I've got the switch set to motion sensing, it "throbs"...that is, all the bulbs attached, at the same time, start to power up then back off. It's not anywhere nearly close to full power...just enough so that you can see the filament and the bulb starts to glow orange a little...then it fades. This happens no matter what's going on...I could be completely out of the zone for the sensor or right in front of it, flailing my arms like mad.
Regular on and off positions work just fine...bulbs come on and are at full power as to be expected.
So, any thoughts? I don't know if it's the switch itself, the lack of that little shield, a dirty eye...I really don't know.
Usually those switches will turn on instantly with motion, and then turn off after X minutes of no motion. So it doesn't seem right that simply the missing cover or a dirty eye would cause this. Either it would sense no motion and the lights would never come on, or it would do nothing at all.
Are you sure the cover wasn't more .. smashed .. off which may have damaged the eye (and other components) beneath?? Not accusing you of anything, but a poorly-aimed laundry basket corner could have done it.