what is the black box under my 1995 jeep grand cherokee?

[Alex]

i have a 1995 jeep grand cherokee and had to remove the front bumper due to oversize tires and personally i like the look without the front bumper, but underneath/behind the bumper on the drivers side is a black box, it is cracked and makes a ticking noise, someone said it is related to my smog and wont be able to pass until that is fixed, the reason it was cracked was cause i was offroading and fell into a ditch but thats a different story, so does anyone know what this black mysterious box is?if pictures are needed i can post them as soon as i can.Again its just a plain looking black plastic box..thank you.