Hi, does anyone know what is this plug?
Plug is in the engine compartment, driver's side.
For what I use it?
I have car only 2 weeks.

 

it is for something that your truck does not have hence the cap on it They make most wire harnesses the same for all versions of the truck simple design and manufacturing of the parts so some items will not be used on everything.

 

Thank you for your answer, try to find more information about this plugin.