Hello all. I recently replaced the OEM Delco system (Delco AM/FM CD head unit, two dash tweeters, 6.5" speakers in each of the four doors). I replaced the factory system with a Pioneer DEH-S31BT receiver connected to factory harness with Scosche GM02B wire harness, retained dash tweeters, Pioneer 6.5" in front doors, and Pioneer 6.5" in rear doors. My issue is that I did not have sound to rear speakers (thought they were blown) with factory system, and since replacing all components with new, I still have no sound at rear speakers. Help please! Thanks.