The motion lights I have mounted above the garage will just blink on then stay off. How do I fix this problem?

Most motion sensor lights have two dials or some type of apertures to control the length of time the light stays on and the sensitivity of the motion detected. Every motion sensor light I have ever owned,and that has been many, I have had to turn the light on for a certain length of time then turn it off, then on quickly... some have even had a slight tap or click that can be heard as it switches to motion mode. Best thing to do is read the instructions and practice managing the system... some work easier than others...