So around the light, there is 12V. But then There may be The sunshine as well as diode that deliver it again to all-around 1V. That 1 Volt is necessary to provide the alternator the sign to start charging. I am not Great at explaining this like this Obviously, but https://raymondnjjjl.vblogetin.com/38168730/top-guidelines-of-jdm-toyota-4a-ge