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Rear defrost problem - and not the normal issue!

2265 Views 13 Replies 6 Participants Last post by  12 lt
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:

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.
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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.
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.

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 ($$$).



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