Rear defrost problem - and not the normal issue!

Hi everyone - got a 2012 LT with a rear defroster that's inoperative. Here's what's been done so far:


1. After buying car, noticed clip wasn't attached to glass on passenger side. Also noticed the black plastic end holding the part of wire that attaches to clip was slightly melted.


2. Reattached clip using Permatex kit - followed directions precisely, waited 24 hours, reattached wire to clip, turned on defrost, clip popped off in about 5 seconds.


3. Took car to dealer. They replaced clip and replaced end on the wire that was melted. Did not reattach wire to the clip, so I did that. Once reattached, pressed button to turn on, clip popped off again in about 5 seconds.


4. Took back to dealer, they tried again. Now the button can be pressed and clip doesn't come off glass, but does not defrost at all.


5. Figured this was now the issue with the wire harness near the passenger footwell. Opened it up, there was minor darkening of the plastic, but not terrible. Still did the bypass with a piece of 12 ga wire anyway.


6. Checked relay and fuse - both good.


7. Checked voltage at back window and across all grids - all good.


8. Made a video: https://youtu.be/dL37driAr8g


Any ideas?! Interestingly, after pushing the clip in to the grid to make this video, it popped off the glass again. I'm wondering if the defroster grid isn't shot and the whole window needs replacing... I'm really out of ideas at this point.


Also - mods - I tried posting this as a follow-up to a recent defroster thread... no dice, so I'm not sure what I did wrong. Hope this one works! Thanks, all.