Type-Spaz

So I installed a pioneer Avic D3 unit into my car. Everything was working perfect and I couldn't be happier. But then something crazy has happened... The sound has gone bye bye. When you switch to ipod, or navi, or CD the unit no longer produces sound. By this I mean both musically and by touch. When you touch any button on the D3 it beeps. When you select any setting the buttons and face no longer beep when you touch them. But also, the music no longer plays. You can see the ipod playing, the cd is playing, and the navi is going, but no volume...

To put the icing on the cake for this crazy scenario.. my friend was over who also has a matching D3. We placed his unit in my car and we still had no sound... What the F#@*. So then i put my D3 with my harness and tried his harness and everything works in his car... but my car has nothing?!

I took my wiring harness apart and reconnected every wire and did them properly compared to the electrical tap nightmare that I got it with. I am so lost I don't know what to do... Can anybody help me?!

Also I put my stock radio back in and BAM everything still works. CD's play and radio works and ipod too... Volume is great and none of the speakers sound blown... What should I do or look for?!?!
Thanks,
Zack