I have a Z110bt and I have a similar issue, but my speaker outputs don't work at all. Only RCA outs work. Ever since I bought the radio. I always had an amp. So i never even tried the speaker outputs. I'm down sizing and tried to reconnect it to the factory speaker outs and nothing. I know the wiring is good. I made an 8 wire harness from the amp in the trunk back up to behind the radio to the factory plug. I tried resetting the radio and restoring factory settings but no luck.
Does anyone have any ideas or is the unit no good?