does anyone know what the box under the trunk is

Well it's not A/C I can tell you that. Sounds like you are describing the fuel tank, I will take a look see if I can find a picture

Probably some emissions control equipment. Newer cars burn fuel vapors that used to be vented to the atmosphere.

you were right I followed line up to engine and found test port ,wiped off cover and found it was"nt ac it read evap I asked this question because i put a small hole in the line . I guess if i dont fix it she'LL probably set a code off well tank you all for the help