It's a slender long metallic box which resides below the nav on the lowest part of the component rack mounted vertically at an angle and perpendicular to the horizontally mounted components i.e. DVD Nav unit, CD Changer etc...in the back left section of the cargo area. You will notice a purple plug coming out of one end of it. You will need to remove the plastic holder to the left of the spare tire to access it since it sits just below cargo floor level in the rack. Does that make any sense at all?? It should be secured with two white plastic nuts.