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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.
 

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It seems like you have voltage to the tabs based on the video. I would take the wires off both tabs, and measure the resistance between the tabs with a multimeter. This will be testing the continuity of the grid/tabs to see if there is a break somewhere. I am betting that you permatex repair is not making good contact with the grid. If you do the multimeter testing, and you have an open, or very high resistance (it should be less than 2 ohms I believe), you can try checking continuity (resistance) between the non-repaired tab, and the grid right beside your repaired tab. If it shows a low resistance then you know your repaired tab isn't making contact with the grid.

There was another person on here who tried using the permatex repair with similiar results as you. While it is somewhat conductive, it still added extra resistance which prevent his window from heating up.
I used this kit to repair mine that had broken off
https://www.frostfighter.com/defroster-repair-tab-bonding-kit-2000.htm
Has been working great for 3 winters.
 

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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.
 

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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 ($$$).

HTH.

Doug

.
 

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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.
Good luck. This slant of the window and rear deck make this not very much fun from what I remember. Please report back how it goes.
 

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Discussion Starter #6
The frost fighter kit is doing its heat cure right now. Put a hair dryer in a baseball mitt and set it on the rear deck. Will allow to cool a bit while I put everything away and then test. Stay tuned!
 

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Test successful. The defrost turns on and the clip doesn’t separate from the glass. Interior lights dim when turning on with engine not running, so it’s drawing some juice. Cautiously optimistic. Will check in within a week or so and advise if it stayed attached. Already tons better than the permatex - it would come off within seconds or not draw power.
 

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Snowball test was successful in garage this morning. The result is after about 30 seconds of the defrost being on. Very pleased.

Other pics are the hair dryer aimed at the clip allowing this stuff to cure and a close-up of the new clip with the goo on it.

162033
162034
162035
 

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Figure what's another $50 in to this.
That's a lot for glue. Next time if you have access to an electric soldering solder iron; solder it back on. Its much cheaper and more permanent.
 

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That's a lot for glue. Next time if you have access to an electric soldering solder iron; solder it back on. Its much cheaper and more permanent.

The only problem with that is the heat can shatter the tempered glass from thermal stress... Then you get to buy a replacement back window.
 

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Snowball test was successful in garage this morning. The result is after about 30 seconds of the defrost being on. Very pleased.
Glad it worked out for you. I try to steer everyone towards the frost fighter because it seems to work much better than the permatex. The additional cost might scare some off, but it seems to be worth it.
 
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