Audio Systems: Aftermarket radio installation, chrysler infinity, chrysler radio

Question
I have a 2001 Chrysler Sebring lx sedan. I installed an aftermarket radio into the vehicle with a scosche wiring harness. All the wire colors match the aftermarket stereo on that harness. The stereo powers up when the vehicle turns on and keeps memory. After matching all the corresponding wires there is no sound coming out of the factory car speakers. I have checked under the passenger seat and in the trunk for a factory amp to power the speakers. No factory amp found. I cannot figure out why the speakers do not work. I even disconnected the aftermarket radio reinstalled the factory radio and speakers work fine. Please help. Thank you! Brent

Answer
The first thing you need is an adapter for the Infinity sound system,  this reduces the ground signal and prevents damage to the amplifiers, that are inside the doors,

http://www.oemautosound.com/p-99-oem-interface-differential-converters-headunit-

Once that is installed you need to use the Blue wire from the new radio and turn on the amplifiers (you have 4)
Depending on the radio model it can be a brown or white wire, amplifiers will burn if you don't use the adapters, because the power of the factory radio is only 2 watts per channel
your new radio is 40w x4 or high power  output

good luck