[metroschultz]

If you want to remove it the best way is with a socket. 19mm I believe is the right size. Or you can use an open end wrench to screw it out with the wires attached. Although I would not recommend that strategy. Those brass sensors tend to round out their corner when puled on by a wrench. From this pic I would say the catch is on the back side. you should be able to feel it and push real hard with you thumb straight into the wires then pull the connector off.
I usually use my pocket screwdriver and pull with my hand gripping tight to the outer two side while pushing on the catch.
Be patient.
You'll get it.
S