Oxygen Sensor Installation Question
 

I am about to replace the oxygen sensor on my '88 190E 2.3. I can't figure out how to plug in the electrical end as the wire just goes into the undercarriage of the car. I did not want to pull on it hard for fear of wrecking something. The oxygen sensor is a few inches before the catalytic converter and screws into the top of the exhaust pipe, correct?

Look under the passenger's carpet. there should be two connectors, one with two wires and one connector with one wire. Unplug by pulling them apart. Feed the wire down through the hole into the underside of the car. You'll have to pull the grommet through the hole first. Installation is the opposite of withdrawal.

Many thanks! Makes sense!