Steve W. said:
Unless Hyundai has started using embedded grids you do not have to
replace the rear glass to repair broken grids.
All you need to use to find the broken grids is a voltage meter. One
side of the glass is at 12-14 volts and the other is grounded
that 12 volts through the resistance element printed on the glass is
what generates the heat that does the defogging.
To test the grid you first have to determine which side is hot and which
is the grounded side. Easy to do. First turn on the defogger, then take
the meter probes and connect one end to a known ground connection (body
or chassis) then probe one side and watch the meter. If the meter goes
up to 12-14 volts you have the Hot side. Double check by probing the
connection on the other side and it shouldn't go up much at all. Now to
find the breaks. First Connect the meter to the ground connection. Now
starting at the top grid GENTLY slide the other probe from the hot side
to the ground side along the grid. Watch the meter. Normally as you go
across the voltage will drop slightly as you near the grounded side. IF
it suddenly drops to nothing the grid is broken just before that point.
Use a dab of grease marker or tape to mark that spot. Continue down the
grid marking those spots. (a lot of the time they are in a row, like
something hit them or they rubbed on an edge). Now you know where those
breaks are. You may not have them all because they grid could also be
broken between those spots and the ground as well.
NOW if you plan on having a dealer do the repairs you just saved some
labor, BUT if you want to DIY there are a lot of kits available to
repair the grid yourself. The one I recommend for others is made by
Loctite and is part number 765-1460 at NAPA. It has a brush, masking
device, and the repair compound. You just clean the area with alcohol
and then hold the mask over the break and then brush on the compound.
Once it dries your back in business. What I do is coat the known breaks
and then use the tester to see if I have voltage all the way across now.
If you do that grid is done. If you find another break just repeat the
repair process and try again.