Defogger repair kit. How to repair defroster tabs and grid lines.

Defogger repair kit. How to repair defroster tabs and grid lines.


if your window defogger more commonly
known as defroster is not working at all
or some grid lines don’t heat up and you’re
not sure how to fix it, this 10 minute
video is for you! I’m going to show you
how to fix broken tabs without soldering
and also how to locate and repair damage
in grid lines. it’s easy! And if I can do it
– you can do it. All I’m going to use is
a defogger repair kit you can buy at any
local parts store and a multimeter, even
the cheapest Harbor Freight model will
work for this job. First I need to check
if there is power and ground getting to
the defogger grid so I’m going to turn
the key to the ON position and turn on
the defogger. Next I am going to set my
multimeter to DC voltage…
…and connect its’ leads to the wires going to the defogger grid
As you can see the multimeter is showing I have battery voltage here, which means –
the wires to the grid are fine and the switch
is working. All I need to repair – is the
tab that broke off and the grid will
work again. Now I can turn off the
defogger and start the repair. I bought
this kit at a local part store for about
twenty dollars it includes supplies for both – the tab, and the grid lines repair.
For the tab repair I have: cleaner
activator towelette, electrically
conductive tab adhesive, and sandpaper to clean the surface of the tab where it
attaches to the grid. And for the
gridlines repair I have quick grid
repair compound with a stencil to place
over the grid, small brush, and an alcohol
prep pad. Now I’m going to remove the
broken off tab – squeeze the connector to
release the tab and carefully pull it
out. Then sand down the tab to make the
attaching surface flat and free from all
of the previous materials like the part
of the grid that could have come off
with the tab.
Next gently pull apart the cleaner
activator packet until the green towelette
is exposed. Make sure to not touch the towelette and
most definitely
don’t touch the tab with it. Hold it by
the back of the protective foil cover
and wipe the area where the tab is to be
attached. Don’t reattach the tab to the same place it broke off from, let the activator
dry for at least two minutes. While we
wait I am going to thoroughly knead the
adhesive pouch for a minute or two, until
the adhesive is of uniform beige color.
Now it is time to open the
pouch and apply one drop of adhesive to
the surface of the tab. Immediately apply
it to the grid and hold firmly for one minute
uncured adhesive around the tab may be
cleaned off with alcohol
now I am going to set my multimeter to
resistance to check for continuity
between the tab and the grid. First touch
the leads together to confirm the
multimeter is working properly, then
touch the tab and the grid to make sure
there is connection between them. My
reading is close to zero which means –
I have good connection. And all I have left
is connect the wire to the tab until it
clicks and the job is done! Next I am
going to turn the defogger back on and
look for broken GRID LINES. Set the multimeter
to DC voltage again and
touch the multimeter leads to the
opposite sides of the grid
you should get 12 volts approximately
but my battery is going bad so it’s
showing less. Nevertheless it will be
enough to test this grid.
After checking the voltage between the tabs, I am moving one of my multimeter leads
to the very bottom grid line, taking measurements, progressing towards the other side of the grid
as you can see the closer I get to the other side – the lower the voltage reading is.
which means this grid line is fully functional, and there’s current flowing through it.
now look at the voltage reading as I
start taking measurements from the
second grid line
it stays the same which means there is
no current flowing through this line. All
I’m getting is battery voltage. And now
it’s just a matter of finding where the
connection is lost, finding the area
where the reading drops from full
battery voltage to zero. In my case it is
all the way to the left
this is the area – right here!
Now that we know where the problem is
let’s turn off the defogger switch and
start the repair. First I’m going to use
the alcohol prep pad to clean the surface
we are working on
then remove the protecting backing from
the stencil provided and carefully apply
the stencil over the broken area of the
grid. Make sure there is a good seal
between the stencil and the glass. Remove
all of the air bubbles from under the
stencil. Shake the bottle of repair
compound and using the small brush
provided apply the compound over the
stencil
after applying the first coat wait for
the surface to become tack free and
apply another coat
repeat the procedure two-three times
until there is no light coming through
the repaired area
after applying the last coat wait 30
minutes before removing the stencil the
manual says to wait 24 hours before
using the defogger but I just let it sit
overnight and it seems to work just fine.
Now you can either check the resistance
of the repaired area by placing the
leads on the opposite sides of it
Or turn on the defogger and check for
voltage drop which is what I am doing.
As you can see the voltage is dropping as I
am moving the red lead over to the left
which means this grid line is repaired
and functioning properly.
And this is how you fix broken grid lines. If this video
made sense – please give it a thumbs up
If not – please share your feedback and
experience in the comments. Good luck and
take care

9 Replies to “Defogger repair kit. How to repair defroster tabs and grid lines.”

  1. i have about 11 v coming out of the rear window defroster positive wire but my grid is still not working. any tips on what i should do next

  2. On my rear defroster I have 5 lines that defrosts. Does that mean I have a broken line in the ones not defrosting? With so many how would I fix them? Also there is tint on the window. This is a "new to me" vehicle. sigh

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