Rear Window Defogger

[Scorpion8]

'Ist kaput. Mine has 12V across the two terminals, but doesn't do jack squat. The window defogger tabs look like they have been re-glued and they are still stuck on firmly, but the defogger doesn't do anything and winter is coming again.

Is there anything that can be done short of a new rear window?

 

[michael loibl]

If they are truely "glued" that's your problem. Must be special electrically conductive adhesive. Diagnosing defogger is tedious work. You could jump power from the "hot" part of BOTH wires to any nearby part of the grid with bent paper clips at same time while defogger is switched on and see if u get a spark at second connection. That will show if it is the tab adhesive as problem.

 

[Rcflyer330]

measure the resistance between the tab and the grid should be a very low reading.
next if it was glued on they tent to work for a season then need to be re glued. that is using the permitex kit and the thread locker tab repair kit. if you try and re glue them use the repair kit from frostfighter its a two part epoxy. I have not tried this one but it seems like a better system than the other kits.

http://www.frostfighter.com/defroster-repair-tab-bonding-kit-2000.htm

i just replaced my rear window (today) because I had to fix it every year due to the grid and tabs breaking. I used the permitex and thread locker tab repair glue and after a year the grid would not work until I broke the tabs off and re glued them.

 

[ABNTGR]

Test the grid again. In a working system you have 12 volts on one end (Passenger side if I recall correctly), about 6 volts in the middle and almost 0 volts on the other end. If you have power at the tabs and 12 volts all the way across then your tabs aren't working correctly...no resistance....most likely your driver side tab has bad connectivity. At least that was the problem with my 2009. Don't waste your time with the $10 kit at the auto parts store. I need to order the one from frost fighter listed above....hopefully it will work better!
Be careful breaking the tab off however, it's is basically silk screened on. I knocked the tab off after the $10 kit didn't work and I pulled up a dime size piece of the side bar.

 

[Scorpion8]

Thanks. I think I've used both the Permatex and the Thread Locker kits, as I know the adhesive has to be electrically conductive. When I measure the grid voltage I measured from one tab to the other, so somewhere has to be passing the voltage across. I'll try from one tab to a spot just a short distance away and see if the grid is getting the power or it's going path-of-least-resistance around the grid or something.

 

[Rcflyer330]

measure from the side of the grid to the other side of the grid see if you get 12v. if not check from one tab to the opposite side bar for the grid see if you get 12v. repeat for the other tab if you get a reading of 0v the tab you are touching is the one not making connection (also try to not press very hard on the tabs it can cause a false reading from the pressure)

I have dealt with this for the last two years with the tabs using the two kits. After about a year they quit working and it makes it very hard to find the tab that is not making the connection to re glue.

this year after i purchased the $14 permatex kit to repair it again and it did not work and i said this is not worth my time or money and replaced the window. i did not try the frostfighter one but from reviews i have read it works a lot better (i believe safelite uses a two part conductive epoxy for tab repair)

I was dealing with broken lines for 3 years and tabs for 2. Over that time i spent about $250 trying to fix the problem just to have to do it again the following fall. carlite glass from safelite with install at full price is around $700. safelite glass was around $400. and on ebay you can get aftermarket glass for around $250 and do it yourself.

 

[gadourym]

I had a problem with one of my wires becoming disconnected from the glass. We just re-soldered it on and it was fine for a while, but came off again. There is very little slack in those wires, so the slightest movement rips them off. This time, I soldered a short piece of wire between the original wire and the glass. It works perfectly, and there is just enough slack to keep it from ripping off if I hit a bump or shut the glass too hard.