I have a 2007 Gen 2 Prius with a bunch of options, but not top of the line option package. I believe it's package 3 or 4. I was under impression that my car did NOT have heated sideview mirrors. Last night I was in a very foggy area and the sideview mirrors fogged up really bad. I could not see anything in them. I turned on the rear defogger and noticed that the mirrors started defogging! I am pretty certain that last winter I tried defrosting the mirrors when they were iced up and decided based on evidence that they were not in fact heated. Now I am confused. Does anyone know if the sideview mirrors are heated on these cars by default? Is it an option? Is there a way to tell? There is no icon indication heated mirror function, which is usually present on mirrors that do have it. What say you?
You could always grab a thermal gun and see what you get . If it is warmer than the surroundings, you have your answer.
One wrinkle there is that the mirrors are quite, well, reflective (in infrared as well as visible), so the thermal gun is likely to show you the temperature of whatever it sees in the mirror. That might be you, and you might be warmer than the surroundings. You can get a nice image with a thermal imager, if you're careful to get an angle where there's not much thermally-interesting stuff (including you) reflected in the mirror; then you can see the exact shape of the heat traces on the back of the glass. Another trick that works is to temporarily cover the mirror surface with something like black tape or sprayed PlastiDip, read that with the gun, then peel it off.
Thank you for the replies. It just seemed last winter when I turned on the rear defroster in hopes of melting the ice off the mirrors, it did not work. Or at least it didn't appear to work bearing in mind my expectations and familiarity with Volvos, which is what I drove for many years up to last year. Volvo really deals with winter weather very well. Rear defroster and sideview mirrors defrost in minutes once that appliance is called on. Also, the cabin heat in the Volvos I had was enough be hot in -20 F weather. I love my Prius, but dealing with winter weather is not its best suit. The cabin heat is weak when it get real cold and the defrosting functions of both the rear window and mirrors is enough to be mistaken for non-functioning or non-existent. Yesterday's experience took place at around 50 degrees F and lots of fog. Enough fog to condensate on the mirrors. The defroster worked on that pretty well and actually made me realize I have heated mirrors. Last winter during the usual winter wonderland event in New England I experienced no useful function out of those mirror heaters. I think Toyota uses under-powered elements to save energy (after all, this is what Prius is about). I don't think there is anything wrong with my car. It functions very well in all systems, so I have no reason to believe there is a malfunction. I believe the design is such that performance is compromised in favor of energy conservation.
Have you, by chance, had ECO mode turned on? I usually do, but it does make some heat and A/C compromises in the name of efficiency. The one that matters in cold weather is that ECO mode locks out the roughly 700 watts of supplemental electric heat that you can otherwise get while the engine is still warming up. 700 watts is a pretty modest amount in a cold car (the regular heater is worth about 5300 once the coolant gets warm), and you don't distinctly feel a difference, but I will turn ECO off if I get into the cold car and the windshield is frosted, because those 700 watts do make a noticeable difference in how fast the frost starts to melt. Edit: but then, I've got a Gen 3, and you probably don't have an ECO mode. Sorry for the noise. A friend of mine has an old Volvo, and I remember seeing in the manual for that car instructions on the optional gasoline-burning cabin heater accessory.
Volvo heaters are amazing. In -20 degrees F you can be super toasty in the car and will not need to turn the temperature knob all the way up after the car warms up. Those mirrors de-ice in pretty much any situation that I have experienced in minutes. They become warm enough to dry water drops on them and the function is restored fully. Ditto rear window. I am talking a 1998 Volvo S70 and 1993 940. As for car is old and is not functioning as it should, I do not think so. It functions perfectly in all respects, gets great fuel economy and is a pleasure to drive. Except for very cold winter weather. Then it's chilly. It's easy to forgive, though as it is a great car otherwise. I just wish the resistive heating elements in the rear window and sideview mirrors were a little beefier so as actually perform the function they were meant for. Gen 2 Prius does not have ECO mode.
I seem to remember the side-mirror heaters are on a timer (15 mins) (see p. 213, Gen II Destruction Manual) …just sayin'
Me, I tend to keep the heater set for 65°F ... and a little 12 volt, 40 watt heated blanket in the car. Instant comfort (sometimes I don't want to get out). Doesn't help de-ice the mirrors though. I wonder what the wattage of those is, compared to the Volvo's.
