I had a question about the rear defroster or defogger. The bottom window works to clear surprisingly fast. The top window not so much. It seems to take a very long time for the window to clear. The lines cut through the fog much weaker than the bottom window and if I have the heat off in the front the back window is pretty much fogged over except where the heating elements cut through. I pulled off the trim on the hatch and checked the connections and they seemed fine. I don't have a voltmeter so I couldn't test the juice going to the window but I figured if the elements weren't doing anything it's possible there was no power making it to the window but I can see it barely cutting through. I guess my question is, am I over reacting and is this normal? Should I call the dealer? I purchased the car used in the summer so I wouldn't have been able to tell. Also I purchased the Platinum warranty but I don't believe this covers the glass (if the elements are burning out).
I can't say if yours is broken or not but I know mine reacts similar to yours. I put it down to the top screen being glass and the bottom one being perspex/plastic. I also notice that the gap between the elements is wider on the bottom screen, so maybe the perspex heats up quicker than glass?
I guess I never realized that they were different material. I would assume that probably has something to do with it....
It is possible that the back window may defog quickly when the front defroster fan is on Max w/ outside air. In Hawaii where morning temp in winter can match the dew point, all of the windows can fog up instantly and one is driving totally blind. This is why you will notice the natives always driving with thier windows open. Native: People that live in Hawaii. It's all about air flow past the glass.
Silly me, I thought this was because those cars needed a recharge of Freon... I think that Grumpy is on the mark.
Yeah I think you're right. I'm going to wait another week when it snows here and see how it performs on the exterior too.
Digging out of the seventh snow storm (and it's not even winter yet) in Minneapolis and I've put the rear defroster through its paces. I thought something must be wrong with my car which was new in April -- the upper defroster is very slow and even downright ineffective. These other postings lead me to believe my alternate theory -- Prius has to be miserly in its distribution of current to accessories. I believe it is underpowered by design. It's going to be a long winter.
I forgot to mention on this thread that the connection to my rear defroster was indeed bad. I figured this out after the first snow storm and the snow wasn't melting off the back. Thankfully we have a wiper back there so I was okay for the brief period of time.
I had a similar issue. My upper defogger stopped working completely. I took it to the dealer and he finally figured out that it was a faulty resistor. After they replaced it both defoggers were working.
I am having the same problem, the top window are not defogging well as the lower one. I took it to a dealer near by me and the service advisor swears the defogger lines are radio antenna and the prius dont have defoggers. That all the cars back window lines are radio antennas........I do have windows tinted, hope it can be fixed without removing the tint. obviously at a different dealer.
wow... I would go to another dealer. Do they not see the little stub on the roof called the antenna? Not all Toyotas have glass-imprinted antennaes. The Corolla, Camry and Avalon do but the Yaris, Matrix and Prius don't. And what car doesn't have a rear defogger nowadays?
If you are looking at this because your 04-09 rear defrost is not working note my 2005 (240K in Fall 2016 Midwest) rear defrost operation was restored by fixing an overheated connection between the wiring and the heater on the glass on the passengers side bottom right corner under the black plastic trim between the top and bottom of the window. Got to love a visual inspection providing bread crumbs.
OK, I'm facing the same issue here...my connecting wire was burnt/brown, although it was still delivering current. I briefly got the grid to work by jumping the connection (stuffed a little tin foil under the tab to the grid), but the connector got hot to the touch and then the defroster tab popped off after having it connected for a few seconds. Obviously I have to re-connect the rear defroster tab to the grid. But do I need to replace the connector, too? I know the resistance of the grid should get warm, but is it normal for a connector to get that hot? Daveatm14, if you see this, did you have to replace the connector itself?
You had a loose fit between the connector terminal, and the tab on the grid. Poor fit equals high resistance which causes heat when current flows through it. That caused "burned" looking wire and the tab to "desolder" - pop off. Repair can be a little dicey. Replacing the wire and connector is easy enough (you want an OE connector). The fun part is the tab. I think the aftermarket has a kit out there to glue it back on and conductive paint to make functional. I don't know what the factory used originally. I found GM service bulletin # 03-08-48-006J which mentions using (silver bearing) solder to reattach tabs on their cars' defroster. Posted via the PriusChat mobile app.
