Testing a Window Defroster Grid

How to locate opens in the grid of a window defroster--so that they can be repaired.

[@demagchevy]

Simple and to the point, my favorite kind of video!

[@djphamtom]

Very helpful! Been trying to tell Toyota that my rear defroster isn't working. Looks like I'll be the one fixing it. Thanks a bunch!

[@Puertoricanmarriedtofilipina]

Thanks a lot Justin Miller for posting your video on Testing a window defroster grid please keep posting more videos on here is really helping me a lot .

[@tomvarley4344]

Thank you for the information, I assumed that the printing was insulated !

[@andrewr7585]

Excellent video. Thank you.

[@telosfd]

Yes sir, very informative!

[@dammit7045]

Great video. 👍

[@unclefreddieDied]

thanks for posting!

[@dynomike1964]

Thanks great video .

[@morrismckinnon6047]

All that's left on my car is the orange colored factory glue that the conductive grids were bonded too!

[@michaelmurdoch5019]

Your awesome

[@TheSuperHellraiser]

i suppose you had to turn on the defroster to check the connections on the grid right?

[@nehuge]

So on the repair kit, where you paint across the broken spot, does window tint affect that painted connection?

[@JustinMillerAutomotive]

If you have aftermarket window tinting film that is installed on top of the heater grid, it prevent your conductive "paint" making a connection.

[@amr-50]

Thanks for the video From where should i get this tester ?

[@JustinMillerAutomotive]

Anywhere. You can buy a 12-volt test light online or at just about any auto parts or tool store. You can get them for only a few dollars.

[@amr-50]

Justin Miller thanks

[@RobertMorodan]

what if my defroster works very slow. it takes 10 or more minutes to defog even. it works but not like before? thanks

[@travyb1401]

You may have excess resistance in the circuit so there's not enough voltage getting back to the window to power up the defogger. /There's voltage getting there just not as quick or as much voltage as there should be in a given time. OR your system is just designed to work slow.

[@TheOriginalguns]

I have an 05 Honda Accord. Only one strip works. There are no visible leads going to the window. Where do you suggest I start the investigation?

[@bigsparky8888]

get an Ohm meter and check each line be careful not to scratch through the lines...no more packages or stuff against the back glass...this is how it gets broken...Sparky

[@dharmaboy75]

What do you suggest doing when the windows is tinted?

[@JustinMillerAutomotive]

If you are careful, you can usually poke your test light lead through the window tinting and touch the grid.

[@jordanleblanc4699]

Can you test it from outside the window? i assume i would have to remove the window tint, apply the conductive paint let cure and re apply tint then?

[@shekitty35]

Will a broken grid cause the battery to drain when the car is parked?

[@JustinMillerAutomotive]

No. An open circuit will never cause a parasitic drain. You can watch my video on diagnosing parasitic drains for tips on how to narrow the problem down: kzbin.info/www/bejne/j5mmaaugatt7i8k

[@antoniorenteriaa]

What product are you using to test the grid?

[@JustinMillerAutomotive]

It is called a 12-volt test light.

[@sistersin2010]

My defroster stopped working, I thought it was the button because it doesn’t click in when you try to use it and no indicator light on dash? Had a different button put on and still didn’t work. They said no power at the grid and no way to fix without replacing the whole window? Any suggestions?

[@JustinMillerAutomotive]

Check for power and ground at the grid again now that you have a new switch installed. If you are missing either the power or the ground, use your wiring diagram test to narrow down the source of the open circuit. If you have both power and ground at the defroster grid and it is still not heating up, then something is wrong with your grid.

[@raulmunoz2022]

Can i test it with the black film on it?

[@JustinMillerAutomotive]

Yes you can - as long as you carefully poke through the window tint film with the tip of the test light, without damaging the heater grid.

[@canas4182]

if one line is broken that leads to the whole system not working? I just removed the tint and my defogger stopped working!

[@JustinMillerAutomotive]

Each individual line in the grid is its own circuit. Breaking one of them should not have an effect on the others. If none of them heat up, either you broke all of them or the connection has been broken at one of the terminals on the sides of the window. Use a test light to figure that out quickly without guessing!

[@canas4182]

Justin Miller thanks for reply i will need to remove pillar trim. I should test with the defogger button ON?

[@JustinMillerAutomotive]

Yes. Turn it on and then measure voltage at the terminals. You should have around 12 volts.

[@canas4182]

Justin Miller i don’t have 12v its 0v everywhere, plus when I test the continuity of the grids with the resistance mode of the multimeter, none of the grids bips!

[@oodavidyyf8416]

What it is when your test light light up when connecting from left negative and right positive but doesn't light up on any of the orange light. What can it be. I don't see any crack on any line

[@JustinMillerAutomotive]

Either all of the grid lines are open or perhaps you have a film (like aftermarket window tint) covering the grid so that your probe isn't contacting the grid. If this is the case, you can carefully poke the test light probe (or a pin) through the tinting film until it contacts.

[@oodavidyyf8416]

@@JustinMillerAutomotive ty realize all my grid line were mess up from previous removal of tint. Had to replace whole rear window

[@chaplainchuckles]

Using a test light on the grid can damage the thin lines, it's better to use something blunt not sharp!