OK my 1987 Blazer has never had anyone monkey with running wires in the door sill area. I was taking the little plates off and removing the rubber matt when I found this. The two little holes on the lip where the rubber goes over for seal had black heavy duct tape over them on both sides. I got all the dirt out and was wondering about this so I went to the donor truck I have and looked at the half rotten rocker on it and sure enough there was the darn tape on the one hole that was left. Was this a coincident or a GM employee screwing with the trucks. Wonder if any one else with solid rockers had or have this on theirs. BTW my truck was in North Dakota so never saw salt only sand.