The previous owner(s) cut the wire right from the second O2 sensor, I have no idea why. I've looked underneath the car and cannot find the harness or where any of the cut cables are! So I would like the see if I can track it down inside the car. I've tried searching and no luck, sorry if the thread is out there! Pictures would help.

 

Rear O2 wiring runs under the passenger seat carpet. Pull passenger seat out and carpet back.

 

Awesome thank you! I will pull the seat out tomorrow and see what I can find. The check engine light is driving me nuts.