Does anyone know what the green plug in is used for? its in behind the black trim piece under the AC controls.

 

Im guessing there is nothing on the front of that panel? There are an assortment of things that can go on that panel. Most trucks have the same wiring harnesses so the build a place to snap a plug into the back of the panel to keep the wire harness form just rolling around loose. In that place it could be either TCS, or backup alert on/off switch.

 

nope theres nothing on the front of the panel, its only the opening for the outlet for a car charger. Its a 2006 lariat if that helps at all, I tried following the wire but I couldn't find where it ended

 

It's for either traction control or backup alert on/off switch. Your truck has neither so just ignore it.

 

Back-up sensor on/off push button switch.. your truck did not come with it.