Did you get it figured out?
Is the grill ABS plastic? IF it is, there is a great way to fix it that I read on Moparts.
First you need to find another piece of junk ABS to use. Next, you use a knife to cut some slivers of ABS from the junk piece. Put them in a jar with some Asitone and they will melt into a gell.
Open up the cracks in your grill and taper the edges so you can get plenty of new plastic into the crack. Once that's done, smear the melted ABS gell onto the crack and let it dry. Once it has dried, you can sand the area and finish it off.