They usually come with clips that you put on the backside of the lower grill. Once the clips are on, you attach the zip ties to the clips and then to the grill. Holds up really well, mine havn't fallen off and I've been plowing through snow drifts and the lower grills are packed with snow...
melt em' on. lol
Take the time to just order the clips through GM
Hard to do that when the grills are metal. :th_scratchhead:
heat up bumper, press grills into soft plastic. plastic gets hard again! bumper is melted to the grill! lol. i'm j/k.