Chevy & GMC Vans

This is that rubberized sheet that is attached to the greyish trim that the fog lights poke thru. The trailing edge has not been screwwed to anything for a long time. It was sorta fastened with zip tys to the sway bar. Well, some days ago it was just flapping in the wind because the zip tys came loose.

So I went to re-attach it properly with screws but it was not obvious to where. So I zipped it again. Where should it be attached to?

One side note, when it was just flapping I noticed that the temp gauge went up some. Coincidence?

Thanks..........