I tried to install a Kenwood unit, used the Metra wiring kit, hooked up the blue wire to blue wire, and color coded every other wire. Unit powers on, but no sound at all. I have the upgraded factory Pioneer system. Not sure what I did wrong. Eventually I'm replacing all the speakers and hooking up a 5 channel amp with a sub, but until I'm ready, it'd be nice to have my screen with backup camera installed. Any help would be really appreciated.