So there's this plug right behind my upper intermediate steering shaft.Any idea what should plug in there?

 

I have the same rogue plug...I have always wondered what it is for also.

 

Could be lots of things. Sometimes the factory harness includes add ons that the dealer can do. Fogs, PTO, security system for example.

 

mine had a plug just hanging around...on mine it was the data port for the computer. My adrenaline fueling box plugs into it so it can read data from engine sensors, and it can modify fueling and timing maps on the fly.

That said, it may be a data port for your engines computer?