mofologic

picked up bosch part # 13275 (ford taurus) oxygen sensor which has one black, one grey and two white wires. searching archives seems to indicate that the 2 white wires can be connected in any orientation to white wires on factory harness for heater loop and black wire to black wire for ecu signal. do i ground the remaining grey wire on the new sensor? that is what i have read seems to indicate. just want to be sure while i have a chance to get it on a lift (i get disoriented too easily laying on my back under the car on ramps).
thanks in advance
joseph