That goes to your ignition switch positive. That way it has two positives. One is a constant to do things like hold memory, keep lights on, provide power to amplification circuitry. The other positive lead just tells the unit that the ignition is switched on, off, or in accessory position so your unit knows when to turn on and off. If you need further help, I’m available over the phone at https://www.6ya.com/expert/michael_4c629b5aef073a57
