My tahoe has bose but no onstar. I bought the gmos04 harness. All the speakers are wired correctly. We have no sound. Do I need to connect the blue/white wire on the RCA harness to the blue/white wire on the gmos04? Also the mute wire on the RCA harness is yellow/black, do I need to connect that to the parking wire and ground wire or can I just ground it by its self? There is a brown mute wire on the gmos04 harness, do I need to connect that to the yellow/black mute or just leave it be. Sorry for the bad gramar. Any help would be awesome thanks.

Yes. You need to hook up the blue and white wire. That turns on the amp. For the yellow wire, you need to do a search on "bypass". There is lots of info.