What is this?

[LedFloyd900]

As I was replacing the passenger side exhaust manifold and gasket, I stumbled upon yet another capped off electrical connection done by the PO. Anyone have any idea what this is SUPPOSED to go to? 1992 3VZE T4R (and pic is sideways, the right of it is the passenger fender well, left of the pic is the engine)

 

[mikekfr]

If that's at the bottom, my pickup has it too, and it's unhooked. I have one very similiar down at the bottom of the driver's side of the engine,up near the radiator, i figured it was an option i don't have or a test plug of sorts, seeing as everything is working as far as i can tell, under the hood. I'll keep an eye on this thread to get the 411 though