I did look at the pin numbers.
It says from the Radio it goes to Relay.
But i traced it and noticed it does not go to relay directly but instead it goes to the plug located near amps ( it does not go to amp at all) and then connects to both to the wire coming from relay and the one that comes from ignition's pin #10 as it seems it has the same color. (I think) So basically the wire that comes from ignition's pin 10 (0.75 vi/ws) and relay's pin #2 (0.75 vi/ws) join together and feed radio's pin #16 as one (1.5 vi/ws) The short is happening in the wire between the plug and the ignition.
But I am not still confused about this diagram, it doesn't make sense to me yet ( the part that goes to ignition)

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2003 X5 4.6is
2001 530i