O2 sensor and other questions

After doing an OBD2 scan on my 96 XJ 4x4 Country because of a CE light, the result was I have a bad O2 sensor. I went under the XJ to look at where the DS sensor was and how accessible it is. While under there I saw the plug from the sensor was unattached to anything. It was just dangling. The I also noticed a second plug that was also dangling and unattached. It was a cable that was attached to the transfer case. My transfer case is a NP231. The plug/cable goes into the X-fer case housing but the other end which has a plastic plug is unattached to anything. The plug is black plastic, female, a couple inches long and circular. Where does it go and what does it do?

Also, I have done a search online and came up empty. I have a 95 and 97 FSM and I can't find anything on what the plug goes to or what it is for. Thanks for any input.

Pictures ?

I will try to do that later this am.

I can't post attachments even though I've been a member since 2007.

www.fototime.com is free.

does you 4wd light come on when you put it in 4wd?

I will check.

Yes, My "Part time" light comes on when I shift into 4wd.

I'll repost over at Jeep Cherokee Forum. I can post photos there.