A:Answer This unit has an audio-sense remote output. Meaning when the radio is turned on, it senses an audio signal and sends a 12 volt signal through the remote output wire from the line output converter. That remote output wire needs to go to your external amplifier (2-channel or mono sub-amp) to signal it to turn on.
The wiring is as follows:
Yellow = battery +12v input
Black = ground input
Blue = remote +12v output to amplifier
White = left front (+) input
White/Black = left front (-) input
Gray = right front (+) input
Gray/Black = right front (-) input
Black/White = reference ground (-) (reference ground optional if noise is present)
Alternatively, the speaker inputs can be wired to the rear speakers depending on your application. I used the rear speakers on mine to add a subwoofer amplifier. That way I could use the fader of my factory radio to give me some limited gain control to the subwoofer. By fading to the front speakers, it will decrease the output from the subwoofer.
Here is a link to the install manual:
https://metra-static.s3.amazonaws.com/documents/INSTAX-MLOC725_web.pdf
