Maybe someone with radio experience can help me out. I bought a 2003 ls with an aftermarket radio in place of where the cd changer used to be. With that said only the a/c and radio screens show up but no nav because the box was removed. I went ahead and bought a new dvd drive hoping that I could use the maps on the dash but nothing shows up. The dvd drive powers on cause I can eject the dvd but nothing shows up on the screen...did the previous owner butcher the cars nav system so bad that I can no longer connect the dvd drive? I have no idea how he bypassed the cars amp system..the car has all after market speakers and a new amp but I do not know he got the aftermarket system to work...and also there are 3 pigtails in the trunk near the dvd pigtails which I assume should be connected but I can't figure out where to connect them. I will post pics soon, any help would be GREATLY APPRECIATED. Thanks in advance!

 

I experienced something similar when installing aftermarket USB interface for stock Nav system. It seems the stock ML audio needs all factory components to work properly. If you unplug "cd changer" in dash, the nav screen goes wonky, even if dvd drive for nav in trunk is still connected. without CD changer, You are still able to control the a/c but the screen goes back to blank when switching to nav. Audio always shows up as OFF. It seems the system is best left untouched except for adding a USB or bluetooth or aux interface using CD2 or MD changer port.

 

I believe u might be right. But I have seen other people add a radio and still have the nav working. Maybe the mystery pig talks are for the factory amp and I'm thinking that I should reconnect those to the amp.maybe the nav needs the factory amp to be connected.

 

Well I figured it out. When the previews owner rewired the car he disconnected 3 pigtails from the factory amp, i replugged them and the navigation now works again. Just an fyi if anyone ever runs into this problem.