I looked into this in some detail and acquired all I was advised I needed before hand but I have had a nightmare trying to sort so far have made little progress.

I have an audi a3 2003 , the later model (8p I think) it has audi symphony 2 double din tap / in dash cd changer fitted , and has bose system front and back.

I have done car audio install before and had no trouble as it all makes sense to be , this doenst.

So I managed to get the symphony out (shredding my fingers) and installed my new fasicia (singe din) with cage for my stereo, confusion starts with cables.



I have the ct51 – au01 that is always recommended , I also have the aerial adapter

my existing stereo I want to fit is a single din Sony, I have the sony to std iso connector


Ok so 1st thing I wan to do is get power to the unit , no chance, the power half of the iso connector which just goes straight to the iso power cable from the audi doesn’t match up, (looking at pin outs on here Car Audio ISO connector pinout diagram @ pinoutsguide.com ) I have 8 ground, 7 +12v ignition, 5 aerial power and 4 battery – these are on the sony side of the hardness , on the audi side I have 7, 8 and 1 ) so I get no power.

I need a direct from battery power but its missing from audi harness , what happens here ?



I'm not sure I have all connections in my car , I pulled off two aerial connectors , one is std so I don’t see why I needed adapter - one iso connector form the bottom (as detailed above ), nothing in midde iso connector, nothing on side the one, the top one is made up form two different plugs, blue one looks normal but black one looks like its been cut in half at some point and there is a cable joining the two ? sounds weird and tbh I cant understand how the connectors I have to play with are going to get any signal to the bose ? I literally have power with SCV cable in , 2 aerials and the top plug of with only the right hand side section has in pins in on the ct51-au01 and from what I have read these are for CD changer ?