Hi Nick, The wires are for a sender unit, the connector for it is attached to the fuel pump. I tested the one I had by partially lifting the accumulator and powering up the fuel pump, you could see the fuel seeping out the joints, around the area of the large steel band. I had fuel flow to the front but no pressure. I replaced the whole thing and instantly got 4.5 bar pressure. If you lift the fuel pump assembly out you will see the return pipe at the top, this is just a loose push fit, the feed pipe (to lh) is near the bottom and towards the centre of the car and is the same type of fitting as the feed pipe that goes to the front, attached to the feed pipe is the connector for the lh sender unit. I've still got the old unit on the bench at work so if you want to, give me a ring tomorrow and I'll try and explain it a bit better. (07957449484/01403 253706) Regards Dave