Hi everyone, I have managed to get AUX working on my Bosch thanks to a Youtube video:
Bosch head unit AUX tutorial
It is in Turkish but you can select subtitles, which are in Turkish, and then click on settings from where you can select auto translate. You can see in the video he joins two pins with a bridge, the DATA-OUT and DATA-IN. I made a bridge with a couple of spade connectors already attached to wires, that I had in my spares box. I twisted the ends of the wires together and covered the join with heat shrink. The connectors that I used were too big for the pins so I squashed them with needle nose pliers to make them a tight fit. I used some more heat shrink over the spade connectors so as to prevent them contacting adjacent pins. Once I had connected the data-out and data-in with the bridge I turned on the radio, and when I pressed the CD button AUX was displayed. Progress!
Then I tried the mini iso connector. When I inserted it, it knocked the bridge off of the pins. I then modified the connector block by slicing off the corners of it so that it would slide in without disturbing bridged pins. I should mention that I had already bent the bridged pins, as in the video, to make room for the connector block. When I tried putting the connector in again..nothing. Hmm.
I compared my connector with the one on the video and saw that the wires on mine were in the wrong order. I managed to remove the wires and rearrange them but I nearly destroyed them before looking on the net to find the correct way! I used very small , thin screwdrivers from a kit I have for spectacles. Looking from the opposite end from where the wires go in to the block, slide the screwdriver down the sides of the metal connector, one side at at time. This pushes a small metal tab back on either side, which allows it to be released.
As in the video, the yellow wire connects to the pin AF-R, the white wire to pin AF-L, and the red wire to the pin between those two. Use the photo below for reference.
With the wires rearranged, I plugged in the connector and bingo, a working AUX input!