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I think I do have a short in the wiring (which would explain the burning smell). I checked my new glass after it was installed with an infared temperature gun (like you HGT) and within a couple of minutes of the defrost being on it was reading 180 degress at the pads. I could barely put my hand up to it. If I took it off the pad and checked a spot around it the temp was around 85. I did it around 745 last night so it wasn't during the middle of the day in the heat. I also had my car turned away from the sun as it was going down. I guess now I will be searching for the short.
Also, the glass I got was used and the people that installed it came out to my house (I wasn't there). The rubber moulding that's under the glass has holes and tears all in it. Needless to say I'm not happy. This is the fourth glass I've had this place put in and I never had a problem before. They actually replaced my rear glass a couple of months ago because the defroster tab kept coming off (despite me trying to solder it back on). That one looked fine, this one not so much.
lol if you look at my picture in here I had to solder mine back on as well. Wonder why they tend to fall off?
What the terminal is attached to is a silver Ceramic. Not the best connection and it is conductive all the way across the glass. You can take a test light to check for cut tracks by starting at the + end and slowly drag it across the line. The test light will slowly dim. If it doesn't dim while moving there is a break and you will find it right when the light goes out. Back in the Dealership days when the salesmen were pasting the in-transit in the back window, customers were removing them with razor blades cutting 3 or 4 grids open.
The weight of the heavy wire going to the terminals were breaking them off which is why you see most now are short or coiled.
lol if you look at my picture in here I had to solder mine back on as well. Wonder why they tend to fall off?
I noticed that...Mine was broke when I got the car. I tried the kit with the conductive adhesive and it lasted a couple of weeks. Then I got some bearing solder and that worked for about a month. Did it again and the same thing, I finally got fed up and just got a used replacement put in. I guess it worked so good that it cracked the glass lol. It was fine for a couple of months so I'm wondering if I pinched/nicked a wire or something putting in rear speakers a couple of weeks ago. I didn't fully remove the package tray (whatever it's called) so who knows what I may have inadvertently done. It was hot as **** and I was just trying to get the speakers in.
What the terminal is attached to is a silver Ceramic. Not the best connection and it is conductive all the way across the glass. You can take a test light to check for cut tracks by starting at the + end and slowly drag it across the line. The test light will slowly dim. If it doesn't dim while moving there is a break and you will find it right when the light goes out. Back in the Dealership days when the salesmen were pasting the in-transit in the back window, customers were removing them with razor blades cutting 3 or 4 grids open.
What you're describing is to check for a cut or open grid line right, this won't help me find a short? If I do have a short (which I'm pretty sure due to how hot it got in a short time) then the light would just be bright all the way across right?
With the new (used) window in, does the defog work?
Does it shut down on its own?
Do you smell anything now?
A short to ground would not light a test light anywhere in the grid area and should pop your fuse as long as no one replaced it with a much higher fuse.
When I checked my current draw the other day it was starting out around 18 amps which is lower than if it were cold. Notice how quickly the current drops and levels out as the grid gets to operating temp.
It does work, haven't checked with a meter but I can here it strain the electrical system when I hit the button.
It hasn't ever shut down/timed out since owning the car. It's about a 20-25 minute drive to work and it'll stay on the whole time unless I turn it off. I tried a quick search last night to find out how long it's supposed to stay on (15 minutes I think) and what controls it (didn't come up with anything but it was a quick search).
I only ran it for a couple of minutes since it got so hot in such a short time but I did not smell anything. I don't want to chance having to get yet another window. The wires right there at the connectors looked fine.
If you have an ammeter that can measure up to 20 amps you can check its current draw to see if it is normal. I think your probably ok with maybe the exception that the BCM is not shutting off the relay.
Do you have a 12v test light?
There's a test I would like you to try with the test light.
If you want to sacrifice a couple fuses, you can replace the 40A with a 20A. If it doesn't blow your fine. If it does try a 25A.
To avoid blowing too many, run it for a minute with the 40A then switch to the 20A. That is right at its normal current draw when warm. If the 20A or 25A hold, it is not shorted. A test light test across the grids would also verify.
Do you have a 12v test light?
There's a test I would like you to try with the test light.
If you want to sacrifice a couple fuses, you can replace the 40A with a 20A. If it doesn't blow your fine. If it does try a 25A.
I ended up getting a test light. What's the test you were wanting me to try?
Ground your test light lead to a good clean ground. If the lead is long enough, you can ground to the driver side pillar door striker.
Using the pic below, test each grid. "Rear window cannot be tinted"
Start the car and turn on the defogger
Starting from the drivers side, first check for a bright light at the section where all the lines leave from.
Working from drivers side to passenger side, lightly touch the grid. The test light should dim more the further you work your way across as seen in the bottom test lights.
Dimming means the grid is not broken.
If the light reacts like the top lights in the pic, the grid has a break and the light will stay pretty much the same brightness until you cross the break in which the light quits lighting up.
Just did it and the light reacted the way it was supposed to (bright on drivers side and getting dimmer towards center). I really think it's getting too hot somehow. In the couple of minutes it was running, the glass was getting uncomfortable to touch.
Like I said, I couldn't find much. One link was some study a high school or college kid did, that was in celsius, but the end result was around 50 degrees farenheit if I remember correctly. The other link I read the person just said not much over freezing, no temp was given.
It definitely gets well above freezing. The only times I've ever used it are to defog the window and it's already well above freezing when that happens here.
These grids are connected to a high amperage circuit to provide rapid heating. The average defroster grid heats to approximately 85°+ F (29° C) and are very effective in clearing rear windows in difficult winter conditions.
I didn't see the above the other day when I was searching.
Obviously it has to get over freezing to melt ice. I would not have any problem holding my hand up to a windshield with the 2 temperatures listed above. I said earlier in this thread that I held an infrared digital thermometer to the windshield and it was over 180 degrees after only a couple of minutes at the pad where the tab is. That and the fact that the damage to the glass looked like it originated from that point is what has me concerned. Maybe it was just a freak accident and I'm "gun shy" since it happened but I'm not looking to replace another glass and have to get it re-tinted again (that'll be the third time in less than a year).
I'll just live with it I guess and make sure to only run it a couple minutes since it doesn't auto shutoff. Thanks for all the help.
08-03-2017, 07:42 AM
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