Just been out to look at mine - I have a few loose cables but none that look like that one....
I also can't seem to find one that looks similar unless it is plugged into the little silver box of tricks right at the bottom.
The SatNav unit should have 3 connections on it - 2 multiplugs with a lever release and the GPS Ariel....
How many pins/wires are in that connection 3-4-5???
I am thinking it could be for the Phone Module...will research RAVE a little more!