I installed my new kenwood kdc-bt648u with the special antenna adapter that connects the the ignition or remote wire... but still no reception except one station lol. Also is there a way to wire the stereo where it will stay on when you turn the car off like the factory radio did? I know there is another power wire besides the constant and ignition, could this be it? I had the symphony radio factory, thanks!

 

I'm pretty sure, behind your C pillars by the back window there is an antenna transmitter which works in sync with the factory radio.