I hope this fixes it for you. I've only ever glued one of these back on, on one of my 2002 Impalas, and it stayed repaired.Just ordered the Frost Fighter - new tab and attachment kit. Figure what's another $50 in to this. I am crossing my fingers for success... you don't realize how much rear defrost is taken for granted until you don't have rear defrost anymore! Thanks for the input.
The reasons I can think of for your earlier attempts not working are 1) too much tension in the wire causing the terminal to break off, 2) surface not adequately prepared before applying the glue, 3) terminal not adequately held in position while glue was setting, or 4) too much resistance in the connection causing it to heat up and soften the glue when the defroster was powered on.
There are probably a couple more possibilities I haven't thought of.
As I recall, the glue was a 2-part mix ala epoxy, with a conductive additive already mixed in (probably some sort of metal powder).
Before gluing it back on, I fiddled around for a while making a jig to hold it in place while the glue set. As I recall, it was just a piece of scrap lumber cut to length to jam in between the terminal and the rear deck. Anyway, the key it to have that part figured out _before_ you mix the glue
If this doesn't work, the only other ideas I have are to take it to a glass shop and see if they can repair it, or have them replace it ($$$).