Got a new question unrelated to all the previous questions

[PANDEMIC]

Ok in the front of the scooter there is what I believe to be a spare 9 pin (I think) plug with the other half of the plug plugged into it...now I know that my rectifier is AC and if I remember correctly there is 2 ground wires and 2 or 3 positive wires on that plug that read 12.5v when the key is on and scooter is not running...meaning DC...what regulates the DC...The reason I ask is because I was planning on making my own harness using the plug to wire an auxiliary plug and the LED lights and possibly a radio that I wouldn't have to worry about turning off switches everything would go off when the key was off...any ideas or suggestions