I have a e320 2003 and the radio unit doesn't work anymore i thought the display (lcd) was gone . So i when to Mercedes an bought a new head control unit radio for the car and had them replace the old unit.... now the lcd turns on and it has a Mercedes sign(logo) then turns off....i cant play cd's or even listen to the radio....the cd changer will not open...... what can i do?

all fuses work fine,

 

Try the audio gateway, there were a few problems with that on the 211,

 

I am having the same issue. The audio gateway is in the trunk fuse box. I have yet to check that myself as I have the same issue.

I was told yesterday by my son's general mechanic that Mercedes uses fiber optics rather than hard wiring for a lot of the electronics including the sterio system. These sensors can go bad and or shut down based on high temperature. I was told that the dealer can set the temperature higher if you live in an area like mine (Arizona). If I get this resolved, I will post my findings....please do like wise if you get resolution. Thanks.