Audio Systems: Car stereo - No music only slight buzzing, bench test, amp output

Question
I just installed a new stereo in my 99 cavalier, followig the instrustions to the
dot. Now the stereo will come on and it accepts disks and everything seems
to be working fine but there is no sound coming from any of the speakers
except a low buzzing with a slight crackling. No matter what the volume is
the buzzing stays the same. I'm pretty sure that the speakers are not blown
considering they're all making the same buzzing noise. Any advice would be
greatly appreciated

Answer
Either the system is not wired properly or there is trouble internally within the new stereo.

If you can pull the unit out and bench test it then you will know for sure what is going on.  Pull the unit out; power it up with some wires connecting directly to the battery.  Use a known good speaker connected to one amp output. Then check each amp one by one.

Once you know for certain the new stereo is working properly outside the Cavalier you should check each speaker line; you can do this with some extra wires to connect manually from one amp to a speaker line.  Go around until you know all of the speakers are working and that the wires you think are the right ones really are.

This wiring diagram will help you identify the speaker channels, but check it out as well to make sure they are correct or that there are no shorts or opens.

http://installdr.com/Harnesses/GM-Wiring.pdf

Did you use a wiring harness?  You can purchase one for your car at Walmart, Bestbuy, Crutchfield, etc. and it will facilitate greatly the installation of your new stereo unit.

C