I have a 2004 A6 2.7T w/ Bose system.

So recently I had some problems with the stock head unit just straight up not working/turning on. After removing the stereo and checking the wiring with a volt meter, I discovered that there was no power going to it. The other day I decided to do some DIY wiring and rewired the head unit so that it takes the power from the front cigarette lighter. This seemed to do the trick and the head unit was back to powering on and seemed to be working.

Problem I am having now is even though the head unit is on, no sound comes out of the speaker. I am wondering if there is something wrong with the power going into the amplifier. Would this be a viable problem? Where is the amplifier located and is there a fuse with it?

Also, even though I have satellite radio, when I press the SAT button it says "No SAT Radio"... how can this be fixed as well?

Thanks!