I'm trying to switch out the head unit of my 05 A3 from the original concert to a pioneer deh4400. I'm using the PC9-401 harness, everything seems to have clipped in nicely except for the yellow part (just under the 18.0c reading) and the blue wire which doesn't seem to go anywhere. When I try to turn the radio on nothing happens at all. Can anyone help me?

imgur: the simple image sharer

Thanks

 

I can get more pictures in the morning when theres some better light if it helps

 

Please upload more pics so that I can research and advise!