1991 Honda Accord with 2004 Cr-v radio head unit-no sound
 

I have a 1991 Honda accord lx wagon. I recently purchased a new head unit out of a 2004 crv with tape deck and CD player. I installed the unit and it fits and looks great, however I can't get any sound out of the unit. I can get power, and the CDs to load and play and the tapes to load and play. Any ideas what gives? Again, everything works, just no sound no matter what it do to the unit. The wires are all hooked up line for line and the harness matches up perfectly, just no sound. Ideas???

did the original unit have a premium system? some had external amps. did you connect the remote turn-on wire (blue/white wire for aftermarket) to the vehicle harness?

did the unit that came from the CRV have an external amplifier? if so, the head unit cannot power speakers directly.