I purchased a new sensor from ZZP it has 4 wires (black, grey, white, white) - I cut the sensor wires at the midpoint to make the O2 extension harness. I added about 15 inches worth of wire to avoid being anywhere near the headers. The problem is that I didn't mark the white wires. So I have my plug end with those 4 wires & I have the actual sensor end with those 4 wires. The grey & black obviously connect but I don't know which white on the plug end goes with which white on the sensor end?