95 325 conv radio install help

when i got the car there was no radio and all the wires were just there. i have a pioneer radio that i tried connecting. the radio goes on but theres no sound at all. theres no sound when playing cd or radio, can sum1 please help me out here
Your car has a factory amplifier unit in the left rear trunk quarter panel. You cannot connect the speakers out wires of a head unit to the inputs of the BMW amp, wrong signal/voltage levels. You must either get a head unit with line outs and an adapter cable, or a generic speaker to line out converter. Or you can remove the factory amp unit and connect the amp audio in wires directly to the speaker wires so you can just use the head unit speaker out connections.