Three wires doesn't sound right. What are the markings on the connector and cable ?
I have two white sheathed cables each with 4 wires. The ends are marked +5V, -D, +D, Ground (One cable is marked USB, the other is not
Not trying to be wise, but any chance there's still cables stuffed up in the gap between the back of the harddrive cage and the side of the case that doesnt come off ?