Got our 2012 package 5 lesss than a month ago, so we haven't had much opportunity to use the rear defroster. The two times I have used it I noticed that it works well on the upper rear window, but the glass below the rear spoiler doesn't seem to be clearing. The red/orange "wires" are visible in the glass, but don't appear to do anything. Anyone else have this issue? Wasn't planning to head back to the dealer until first service since we haven't had any other problems, but this could be annoying with the winter weather.
That's a shame. Not sure, but I think most of us look through that part of the window fairly frequently - especially those of us who are less than 5'7". I think I'll still have them check it since mine doesn't seem to work at all.
My experience is that the lower part is not as efficient. When I've looked it appears the wires are further apart which I've assumed is because the glass is acrylic or plastic and thus more susceptible to heat damage. Personally I don't really have a problem with the rear window misting up as I use the climate control with a/c on all year round.
Didn't have this problem in the gen II (08). The wires are definitely farther apart on the gen III which makes sense why it would be less efficient. Mine just seems to be completely inefficient. Since I don't need to return to dealer for anything until next month maybe I'll get some more opportunity to "test" it. Clear skies and nice temps for the next several days so it is possible that I won't get much chance to test it before then.
I have the same problem in my 2013 Toyota Prius GenIII, I even took it to dealership. There are two different ideas: 1- the lower part of the window is just a part of radio antenna and is not designed to be defrost. 2- it is not as efficient as the big window even when I have a 12volt throght out the wires.......any good news about this problem?
My theory is since the upper window lays flatter, Toyota engineers allocated more power and heating elements to clear frost/snow/condensation than the smaller window, which sits up almost vertically and therefore has fewer wires. But the side mirrors clear fast though. I haven't noticed any issues with it, but will look for it next time I need to use.
Had to rely on the rear defroster more over the last few weeks. While the lower window doesn't clear well, it hasn't been as much of a problem as I originally thought. Part of the issue is that the lower window gets dirty faster when driving in nasty weather since it is vertical - just like the back window on the cap of my truck. Drive down the wet road a couple hundred feet and it is almost impossible to see through it. Maybe a washer and little wiper blades would help.