Wiring harness behind empty button slot

I've already used the most accessible blank slot in the dash to put in a rocker switch to cut my DTRL off. Managed to pull one of the other blanks out, in an effort to add another toggle switch for some rear-facing lights, and to my surprise there was a wiring harness behind it. What gives?

It's directly underneath the driver-side far-left air vent. Of the three blank spots in my dash, it's the far right one. Has 4 wires going to it- haven't pulled out my test light yet so I don't know if they have electricity or not, but it really threw me for a loop. Easiest answer, anyone?

 

One of the factory features you don't have. I don't remember where - but there is a photo around here of the "fully loaded" swtich panel that you could use to figure out what feature goes there.
Usually the run the wires while the body is all opened up but they do not put the terminal ends or other system components on unless that truck is supposed to have them.