Audio Systems: GM Delco factory HU replacement problem, chevy suburban, bose system

Question
My stock delco head unit in my 2001 Chevy Suburban quit working on me.  I am trying to replace it with an inexpensive aftermarket unit.  I bought a wiring harness and am sure that I have everything connected properly.  The problem is, I have power to the deck, it turns on and works fine, however there is no sound out of my speakers.  The balance and fade are set correctly and volume is turned up.  All speakers worked fine prior to the switch out.  I am guessing it has something to do with the fact that there is a small amp somewhere in my vehicle that runs some or all of the speakers that needs to be powered on by my head unit.  Not sure what to do.  Thanks in advance.

Answer
The suburban has an extra amp to run the rearmost (roof) speakers. Usually if you hook up your deck's blue power antenna wire to the power antenna wire on the GM adaptor harness it will work. This does not explain why you have no sound however. Is this a delco bose system by chance? If so, you will need special adaptors to make this system do anything, unless you run new speaker wire to all raw speaker connections. This is a worst-case obviously. You may just have a shorted speaker wire too.