I have a CPO '06. Living in Southern California I rarely end up using my rear defroster, but I did today and noticed what may/may not be a defect. I wanted to know if others see this as well. Basically, after being on for awhile, only the middle to lower half of my rear defroster (metal bars in glass) seem to be working. They heat up just fine, but the top 1/4 of my rear glass stays cool. There are three or four of those warming bars in the top part of the glass, but they don't warm up. Is this by design? Or should the very top of the rear windshield also warm up? It seems like it should considering that there's warming elements in there.
The area that doesn't defrost is about 4-5 inches from the top.

 

This happens to me too however sooner or later, it will work. I believe that the window sends more power to the lines at the bottom half of the window so that you can see through it faster (or something idk what their reasoning is so don't quote me on that). Just give it time, the window will be cleared off by 5 min, at least that's what mine does.

 

The only area that gets warm is the middle and bottom where there's a larger gap between the rows. The top edge won't clear like the rest.

 

So your never clears at the top (4-5) inches even though there are warming elements in the windshield there? Strange. I think mine does this as well. I had it on for about 30 mins, and the top lines never got warm.

 

The grid in the upper section of the rear glass is for the radio antenna.

 

So that must explain it. The top three grid of lines isn't actually a warming element (although it looks identical?) Is there some literature that confirms this? I thought the radio was integrated into all of the lines going through the rear window.

 

It's in the Service Manual.

 

 

I just bought a 2G TSX and the rear defroster on it sucks. Could just be an Acura thing? The 09TL loner I got had an absolute crap defroster too. :-(

 

Poltergeist is correct the top 5 or so inches is actually the car's antenna but strangly enough electrically it's tied into the heating grid on your rear froster. I know this well as my defroster wasn't working and I had static on the entire FM band ! yeah that was bad cost of a new rear windshield $710.00