Lighting, Light Fixtures, Ceiling and Exhaust Fans - Motion Sensor Ghosts

I installed a motion sensor triggered flood light above the garage to replace the old one my son broke throwing a ball against the wall.

Installation seemed fine and all processes seemed to work; turned on after dusk when motion near light.

Here's the issue - it turns on randomly but is on most of the night. I turned the sensor down to minimum. If I stand near the sensor and wave my arms it barely "notices" me and yet it still turns on alot throughout the night. I've also watched it turn off and on when there was no motion.

Any ideas?

Some motion sensors are just that, and they detect any motion, including tree limbs, and other effects of the wind. The better ones will incorporate a heat sensor as well as motion, so you don't have false starts by tree limbs, etc. I assume, also, you have taken it off "test" mode.