hello friends I'm having a problem doing a sound modification of a discover lr4 year 2010 it came sound common audio system car without gps doesn't have touch touch screen and none of that I'm putting a 7.1 system navigation system optical cables all but I'm with difficulty that the main audio unit ACM does not turn on does not appear in the car can network any friend can help me

 

Maybe go to the LR4 forums and ask them they might help you out