So, there is a number on the end of this wire 968339-2 (B), a quick google query brings me to this...
Mercedes Plug Terminal Wiring Connector A 2105402081 on eBay (end time 07-Jan-11 20:12:50 GMT)
This is the female end of the wire that I have sitting out, and it's saying something about the ECU?! This concerns me... Anyone ideas, please?