RT4 Intermittent sound

[MikeC100]

I have a Peugeot 407 Coupe 2.7 TDI with intermittent audio sound from my RT4. The Display, satnav etc work fine without any dimming or interruption and there is no problem with the RT4 head or connectors i can see on removal. The system has a factory fitted amp in the boot so the audio sound signal goes first to the boot and back. I need to know where this cable runs from front to back because when i lean on the centre arm rest console or bang lightly on the side of the dash the audio sound returns temporarily so there is obviously a damaged wire somewhere in that vicinity. I am looking for details of the wire routing to the amp and also centre tunnel console removal details...or any other ideas! ps sometimes when i put my foot on the brake the sound also returns for a few seconds!! This audio problem affects sound from radio, phone and satnav voice directions and i do not believe it is an RT4 earth problem