The module can remember the light condition when turn on the headlight. If it is dark light, you operate it as: AUTO--headlight--AUTO--headlight--AUTO, then the side lamp, headlight will flash one time and remember the current light condition surrounded. If the recorded light condition's brightness is above the limit that the sensor turns on headlight, the headlight will not turn on at once; it will just make the brightness of turn light condition ahead of the most sensitive condition. But if the current light condition is within the recorded light condition, then the headlight will be turned on automatically.