Where does this plug go into?

I do not know, does not look factory to me, did you buy the car used?
If so maybe it is a add on of some kind from previous owner.

Some one with better insight will chime in, just hang in there.

 

I would agree.....does not look OEM.......

 

Where was it dangling from? Location would help, although I agree - doesn't look OEM.

 

I know they've gotten cheap with the interior materials, but they haven't started splicing wires together with electrical tape as your original pic shows. It looks cobbled together. The previous owner had something wired into it but I have no idea what it was.

 

Probably a cable for the sub prime vehicle financing disablement device, when you don't pay, you don't drive.

 

Take a multimeter to the two pins to read the voltage with the car on and off. If it reads some constant voltage, it is probably an added power supply tap for something the previous owner had. Nearly every sensor on the car has some type of check, so if your engine check light is off and everything else is OK, then the probability it is an unplugged sensor is rather low. Meanwhile the number of gadgets some drivers want to add to the dash is insane....and every one of them needs power.

 

Its for the Tire Pressure Monitor Reset Switch.
The switch is mounted to the left lower IP closeout panel, just to the right of the Diagnostic Link Connector. I've circled it in Red
Are you missing the closeout panel?