Last summer you loaded your
SUV to the gills with antique
furniture. You slammed the
back hatch and off you went. Nothing
was hitting the rear window before you
left, or so you thought. But now that it’s
November and the temperature is tumbling,
you notice the rear window defogger
isn’t working.
Checking the rear window, you realize
that you broke off one of the electrical
tabs for the defogger. Plus, one of the grid
lines is scratched. There’s no need to fork
over the cash for a new window or pay someone to fix it. You can fix both of
these problems yourself for less than $15.
Both repairs in one kit
Most auto parts stores stock rear window
defogger repair kits. The two most popular
are the Permatex Complete Rear
Window Defogger Repair Kit No. 09117
and the Syon Rear Defogger Repair Kit
No. 38-8434. The kits cost $10 to $15 and
include repair instructions. If you only
need to repair the tabs, buy the Loctite
Rear Window Defogger Tab Adhesive No.
21351.
We selected the Permatex kit because
it’s widely available and is a complete kit
for both repairs. The instructions aren’t
as consumer friendly as we’d like, but the
kit performed flawlessly.

The Permatex
No. 09117
Complete Rear
Window Defogger
Repair Kit includes
everything you
need to repair
broken tabs
and grid lines.
The kit costs
less than
$15 at
most auto
parts stores.
Even though the electrical tabs are soldered
onto the defogger grid at the factory,
avoid the temptation to solder the
replacements. If the heat cracks the glass,
you will have to buy a new window.
Using the sandpaper from the kit, sand
the rough solder surface on the loose tab
(Photo 1). Use the alcohol prep to clean
the tab and the grid area where the tab broke off (Photo 2). Then apply the
activator to both areas and let it dry
for two minutes. Next, knead the
adhesive packet until the electrically
conductive silver particles are fully
mixed with the glue and apply the
mixture to the tab (Photo 3). Press or
tape the tab onto the activated grid
area until it stays by itself (Photo 4).
To repair the grid line, simply
attach the supplied stencil to the broken
grid section and paint on the
electrically conductive paint. Allow it
to dry, then remove the stencil. You
may want to touch up your work with
a single-edge razor blade. But be careful.
You don’t want to damage any
other grid lines.
We completed the entire repair in
less than 30 minutes. However, the instructions warned us to wait 24
hours to test the defogger.One last note:
You can only do this repair when the
temperature is above 50 degrees F.
1. Using light pressure, sand the back
of the broken tab smooth. Use the
sandpaper from the kit.
2. Clean the tab and the contact area
with the alcohol prep. Then apply
activator to both surfaces and let it dry.
3. Knead the adhesive packet to mix
the conductive particles with the
glue. Then apply to the tab.
4. Press the tab onto the contact
area. Hold it in place until the
adhesive sets up, usually about two
minutes. Wait 24 hours to use the
defogger.
5. Repair a broken grid line by cleaning
the area around the break
with the alcohol prep. Allow to dry.
Peel the wax paper liner off the stencil
and apply the sticky side to the glass,
aligning the stencil to the existing
grid line. Brush on the conductive
paint. As with the tab repair, let it
dry for 24 hours before using the
defogger.