[Car audio installation] Question install new headunit

Ok guys I have a question about installing an aftermarket headunit in my car


I just got a pioneer headunit from a friend and was trying to install it in my car ..... I went out and brough the Harness Wire adapter for my car ... and matched all the color wires in the back (red = power, yellow = battery etc.) and plug the new adapter back into the car's adapter.


but when I turn on the car the head unit doesnt power up.

Am I missing something else? ... there's a black plug from the car but it says Antenna and the ground wire is not used.

Is there more to just matching all the wires on the harness adapter to the pioneer unit and plugging it back up.


thanks,