My hummer h3 2006 rear window defroster won't work I used a multi meter but I'm only getting 1 volt on whole grid and it won't do crap I use it and let it sit for 15 min and nothing I can't see a break in the grid or a tear and every lune is getting power if any one has a solution or suggestions please respond due to the winter weather I am in need of it desperately so help is urgent thank you.