What Colour wires are what on my Headlight wire loom?

[pcdoctorsw]

Hi guys, i need to replace my headlight wire loom because it's broken. Basically on the bulb connector there is 1 black wire connected with a grey wire, and on the other side of the connector is a single yellow wire. I'm just wondering which wire is the positive?

I've received a replacement part which is the same bulb holder fitment, however it's only got 1 black wire and 1 red wire. So basically in order for me to replace the replacement loom i'm going to have to connect 2 of the wires together. Can anyone tell what what colours are what, or even better which wires i should connect together?

Thanks Gav