How do ya get to the O2 connector ?
 

I have a 1989 560SEL and I need to change the O2 sensor but I can't get to the connector from under the car and the seat and carpet and console have it sandwiched on the inside. Do I have to take out the console to get to it or can I just pull it through the rubber gromet or do I have to take out the seat?I'm hopeing that someone has done this before and there is a simple solution.

On the E-Class cars the electrical connection for the Oxygen sensor is under the front passenger's side fitted floor mat. Typically the floor mat has 1 snap below the front edge of the seat that secures it. Lift to unsnap the floor mat and remove it from the car. Disconnect the electrical connection, then remove the grommet and push the wire through the hole in the floor. Unscrew the Oxygen sensor from the exhaust pipe. Installation is the reverse sequence.

Remove the passenger seat floor mat.

Remove the plastic foot rest looking thing at the head of the passenger foot well.

Your oxygen sensor wires are under there.

You might need to remove the center console side carpeting to gain full access to the wiring.