I own a 95 Mitsu Eclipse GST, I only have the riocar as my head unit.

When I first got it, I installed it.. It worked fine.. When I put the whole unit in it didn't work.. I used the Black(Ground), Yellow and Blue(Amp) .. Basically it looks like theres no power... But when I use the ac adapter it worked fine..

I have a multimeter.. checked the wires working.. it has power.. can anyone help me?