Electrical problem and no one knows what caused it...

Hello,

This will be my first post here and I was wondering about the defogger strip on the back of the 2005 Mazda 3 GT sport. The one strip in the dead middle of the window isn't working but when I took it in for repairs, they tested it and realized that current still travels from one side to the other meaning the strip isn't broken or ripped. However, I tinted my windows so my warranty is technically voided but I know the guy at the dealership so he offered to help me out free of charge. The thing is, we don't know what the cause is for only one strip to stop working because it's not ripped like I said before. Does anyone here have any suggestions or possibly have the same problem and could offer me their valuable insight into this matter? It's annoying in the winter when that one strip takes a long time to defog with help from the other strips right beside it. Also, this is probably a really bad thing to have if I decide to sell it later on (privately). Please help me out and thanks for reading.

I say is is ripped, you will still get current even if it is not all the way through, but not enough of it there for the amperage to make it warm up.
Also, what  did he use to test it? Current will still show at the ends if the middle is gone

Basically, what he said ^ ^ ^.  A partial break means higher resistance at that point.  As we all know from 8th grade physics, electricity will ALWAYS take the path of least resistance... just as water will.
 
There is a paint-on fix for these, usually a copper paint that will fix your problem and restore full current.  The defogger may not work correctly at the actual point of the break ever again (it may work slower than the rest of the line,) but all around it (both sides of the actual break) will.
Either that or replace the entire back-light.
 
 

Something like this might work for you.....mask off the window above and below the line you want, then paint.  (tint would need to be removed.)
 
http://www.midwayautosupply.com/pc-14205-434-permatex-quick-grid-rear-window-defogger-repair-kit-05-fl-oz-15067.aspx

YEAH!!!  ^ ^ ^ That's the stuff!!
 
 

i hear that there are vents that are in the rear view window but apparently they dont work and are for show... actually someone here told me that it doesnt really work and is just here for show... is that true or does it really work?

Wrong thread, Bud, but you have the sedan so do some personal research and you tell us.
 
 

oh wow i could have sworn it was the right thread... oops my fault guys.