Hi all! could you tell me please how to unplug from power Rear both O2 sensors Driver and pass sides? My car is 04 2.7T BEL... there are three connectors Green ,Black and knock sensor blue one. The green ya i know is pass side rear o2 sensor, but can't find anywhere connector for rear driver side...
Please help!
Thanks.

 

Both of the rear ones are black. There are 3 on the passenger side fire wall as you noted. The other black one is located on the driver side.

 

Prior to uninstallation spray some WD-40 liquid lubricant on the connection of the sensor with the exhaust lines, as this relieves a jammed sensor.
to locate the connector follow the wires coming out of the sensor end.