Hi,

Doing a search led me to some scary posts on the rear glass shattering from the defroster. I checked the conections and leads on the glass, it all looks well.

My rear is tinted so I don't want to run into the dealer and have them tell me its casued by the tint.

Any help?

Ashby

2 fuses control my rear defrost check your fuse box for a blown fuse

When they tinted your window they more than likely cut one of the conductors. They did this on mine. I took it back to them and they fixed it for me. It's an easy fix. They sell the liquid copper at most parts places.

You can use a fluke meter to find the cut.

Joe

Top half / bottom half?
Few lines out? Grouped together or separate?
Halfway meaning it does a half-effort job (removes a little moisture, but not a lot?)

What changes have you had since it worked? If you had it tinted years ago and the problem occured recently, it's probably not the tinter cutting a trace. If you just had it tinted, it probably is.

Some other things to check: Did you load something and bump the window? Scratches on the resistor cause a break. (This is where tinting can help you!) Please give some more detail.

Tinting generally isn't a problem--the people who have problems post, those who don't (me) don't put up "My glass didn't break today" posts.

When I tinted my sunroof, I was warned sunroofs shatter more, and they don't have defroster. I expect that's due to more sun exposure; the inside of the car is not and dark tint on the inside absorbs the sun's heat, making one side super-hot and the other exposed to the relatively cooler outside air. I went with the lightest color, metallic-tint to block UV and reflect heat.

Why is this a problem: Think ice cubes.
When you dump them in a drink, the outside surface is warming up fast and expanding (Ice can obviously be colder than 0 degC and I'm referring to the solid expanding). The inside is the same temperature and is not expanding. This change in size causes ice to crack and pop.

When tint is on a window, it contains the heat from the elements more, like a blanket on a body. The other side of the window (outside) is presumable colder. Glass expands on one side from the heat, stays the same on the other, and it shatters from the stress.

If you are really worried, cycle your defrost on and off for the first few minutes.

FWIW, I still don't understand why cutting parallel resistors (heating elements) would reduce overall resistance. I need to model that in OrCad.

Probably more than you want. I was Smiley-sized.

I tinted over 4 years ago and it worked perfectly up till now. In the past 6 months I have used my Rodeo to move stuff so items touching the window could be a likely possibility, though I do see any damage.

Its the top half only. The top defrosts fine while the bottonm is untouched. I will look at the fuses today, didn't know there were two.

**Also should I replace the fuse and try it OR since something casued the fuse to pop should I do further checking (assuming it is the fuse, I will check later today)

THANKS!
Ashby

Wayne, I was under the impression that it was the defroster causing the windows to shatter, not the tint.

It is temperature differential (Dan could probably step in better on this than me). The heat differential from one side of the pane of glass to the other means one side is slightly bigger than the other in a solid object, creating a physical stress.

Normally, part of the heat from a defroster goes into a glass, and part of it radiates out. When you cover the defroster elements with thing, you've essentially put a blanket on them. A thin, lousy blanket, but a blanket none the less. If you've gut the window under a little extra stress then you hit a bump that's just hard enough--it shatters.

That's part of why you can touch a defroster element and it doesn't feel hot. It's just a little bit of heat. More would defrost faster--but your window would shatter during the first cold day when you turned it on.

This temperature stress can be going beyond the factory planned limits with heating elements covered in plastic tint, or by black tint on the sunroof getting full sunlight as you pull out of your partially air conditioned garage in Phoenix.