Car Stereos: 96 Cadillac sts no sound, bose amplifiers, ohm speakers

Question
I have a 96 Cadillac sts w a Bose system and cd changer. I installed a Sony deck in the car today . So with the Bose system in that car the amp is individually attached to each speaker and has a plug into in w four wires. On each speaker Tha orange and black I am presuming are power and ground while the other two should be high level inputs. So I took out the back speakers and replaced them with Sony 6x9's. I cut the plugs at the speakers and used what I assumed are the high level inputs. I also did the same with the front speakers but i used the factory speaker. I used a wiring harness to connect the deck so I didn't have to cut wires. So the deck turns on but I'm getting no sound out of the speakers what am I doing wrong?

Answer
Hi Shawn,

I suspect the problem is in the wiring harness.  Your method of bypassing the amps would work fine, if the two signal wires at the amplifier were simple positive and negative high-level inputs, connected directly to separate positive and negative output wires at the head unit.  However, in a typical multi-amp Delco Bose system, the input wires are a common-ground low-level input.  The outputs at the Bose head unit (or, in many vehicles, from the tuner/amp pack in the trunk) use four positive wires, two "common" negative wires, and two bare shield wires.  This configuration is not compatible with the high-level speaker outputs in an after-market head unit.  

In your vehicle, you'd either need to use an OEM premium-sound adapter to install the new head unit, and leave the Bose amplifiers working; or you'd need to run new wires from each speaker directly to the head unit to bypass the amps.  Unfortunately, an amp bypass might not be a good idea  unless you're installing after-market speakers, because Bose systems often use 1-ohm or 2-ohm speakers that can cause problems with the new head unit.

Hope this helps!

Brian