new radio

just tried installing a Sony MEX-N4100BT in my girlfrinds brothers 2000 chevy venture and it will not turn on head unit is brand new i have power and fuses are good i guess im wanting to know if it maybe the ground even though i have it hooked up through the wire harness if i might have to...

I bought a new Pioneer radio and the wire harness. I had my bro and friends at work look and try nobody can figure this out. I have all the wires correctly positive to negative colors. But for whatever reason only the back left speaker works. I thought maybe I was having problems because of the...