MK1 C4P RT4 Aux and USB input?

[TawhidAhmed]

Hello All,

I have recently bought a C4 Grand Picasso with the RT4 Navidrive unit. I was wondering how to add an Aux input and USB to this system. I understand there is an Aux lead that can be bought that plugs into the back of the system, however, it appears this port is already in use! But by what? It seems to be part of the main wiring loom for the nav unit. I am not sure what to do. I have attached some pictures to show the port. The leads I found online are like this: https://www.ebay.co.uk/itm/163875216349 ... SwJshdh13L

Thanks!

[GiveMeABreak]

On the back of the RT4 unit look Part 'C' in the diagram below. That is where the CD changer port connection would be. So if you don't have anything in there that is where you would connect a USB.

In your last photograph below where I have arrowed in Red, I can see a wiring lead at the back with a brown plug - which looks like it may be for the CD Changer (when fitted). The CD Changer is installed in the upper right glovebox storage unit, but was not fitted at factory according to your VIN. SO this may be the pre-wiring for a CD Changer to make it easier to retro-fit later.