Oxygen sensor disconnected

I noticed that the oxygen sensor for my 1988 Jeep cherokee was disconnected. Could not find the other plug that goes connected to the sensor.Does any one where it is located.

Not sure if it's the same but on my 92 sport 4.0 the connector comes from the wiring harness that also runs for the injectors on the driver side of the engine and then drops down between the power steering pump and intake and exhaust manifolds and is mounted on a bolt in the oil pan.

Yes my 88 Jeep wires run the same way.