There are no breaks in the grid, I verified this by checking for continuity the connectors are fine as well. This is what leads me to believe that there is a break in the wire that comes out of the body and goes in to the top of the door. Seems a little premature though as the truck only has 100k kms on it. Where is the mercury switch located? I checked the defogger fuses as well. I haven't checked the relay but j have funny feeling that it's fine.