Explanation: Plug LED Night Light in the power, when the ambient light is dimmed, the LED Night lamp will automatically light up. And when a brighter light is turned on the LED Nightlight will automatically turn off. The night light will automatically adjust the brightness and LED lights will automatically turn on or off as per the ambient light levels. How do I check if the LED light is working in daylight? Just plug in and put your finger on the sensor in the center of the LED Light to check and the Led light will light up.