The dimmer will cut off the light in the following situations:
a. The load exceeds 120W
b. In a 12V system - the voltage is less than 9V or great than 15V
c. In a 24V system - the voltage is less than 19V or greater than 31V
d. For regular LED lights only - not for high power LEDs lights
The LED next to the + or - key will flash depending on the above situations