I think of all automotive dashboard controls that can be considered among the standard complement of controls of a modern-ish car (as in, from, say, the 1980s and up), the one that seems to be the biggest vagabond, the one that seems to have resisted finding any sort of standard home, has to be the rear-window defogger/defroster switch. It’s also an interesting case where the icon for this feature has been standardized, but in a way that is conceptually wrong, at least based on how most of these work. I’ll explain.
First, think about the cars you’ve owned or driven, and think about where the various controls were. For most of them, there’s certain conventions you can expect: lights on stalks or perhaps dash knobs to the left (on an LHD car) of the wheel, indicators on a stalk, HVAC in lower center, usually below the radio, and so on. Now think about where the rear window defogger switch was on those cars. I’d bet David’s money no car had it in the same place.
Look, here are a few cars from the 1960s to 2010s with their rear defroster switches highlighted:
Are you trying to find some sort of pattern or reasoning behind the switch placement in these? If so, I beg of you, do not, because that path can only lead to madness and pain. Sometimes it’s grouped with the HVAC controls, sometimes sort of near them, but not really, sometimes close to the driver, sometimes not, often they’re just slapped next to the hazard lights switch, clearly slapped there at the last minute in a panic when some quality control somebody was running down a checklist and realized something was missing.
That old Beetle had a little switch under the dash, completely invisible, even though the addition of an extra switch on that sparse dashboard would have made the car look decades more modern. Nobody knows what to do with the damn thing.
Personally, I think the sensible place is with the other HVAC controls, because it does a job similar to the windshield defogger, even if it’s not technically part of the HVAC system. And that leads me to the next mystery of the rear window defogger switch: the icon for it.
This is what the modern accepted look of the defogger switches are – on the left is the windshield, on the right is the rear window one:
So, we have the accepted three-planaria-wriggling-onto-glass convention here, though sources have told me the squiggly arrows are not snakes or flatworms but rather represent air blown from vents in the HVAC system. The front is indicated by the area cleared by a windshield wiper, and the simple rectangle is supposed to remind you of a rear window. Okay, fine.
But here’s the problem: for most rear window defoggers and defrosters (yes, there’s a few exceptions, usually ’60s vintage or so), that’s not how rear window defrosters work. They’re electrical. There are no snakes – sorry, no air being blown to clear the rear window off, it’s just a bunch of resistive elements (wires) in the glass.
When you’re actually using the rear defroster, you can see this very prominently. It’s warm electric wires doing the work, not blown air. And early defroster switches tried to convey that:
See? Those all have icons like little resistive heating coils. They’re much more accurate about how the rear defroster actually works. But this icon is effectively extinct, replaced by the deceptive three-snakes air-blowing one.
Personally, I think the ideal is the old-style, more honest icon on a switch that’s grouped near the windshield defogger controls. That way, it’s got an accurate icon, and the location is grouped by the driver’s needs – get the windows clear – which seems to make the most sense to me.
I’m open to hear what you think about this vitally, possibly even gravely important issue! Let’s discuss in the comments! Hash this out, once and for all, and settle things.
On my Xantia it’s on the wipers stalk, wich kind of makes sense. It certainly isn’t the most stupidly / randomly placed button in that car.
With the other heater/blower buttons and knobs is good. Heated seats should be there too.
But frankly, these days, as long as there are physical buttons I won’t complain.
I find snakes a very impractical way to defrost windows, I don’t recommend it. It would be very hard to direct them to the rear window, and even then it wouldn’t necessarily defrost it. I definitely prefer an electrical defroster.
First-gen Saturns had a toggle switch on the dash, behind the washer stalk and just below the gauge cluster. The icon was to the left of the switch and I think the defroster was actually on a timer.
You can kinda see it here.
Frankly, I think this was ideal. It was near all the windshield-related controls but didn’t crowd up a stalk. Plus, you didn’t really have to take your eyes off the road to turn it on.
What bugs me most about the HVAC location is that it’s usually farther down on the dash and next to the windshield defog button. It’s easy to mix-up the buttons, especially when you’re driving in weather that requires you to keep your eyes on the road and defrost the windows.
On my first car, a Maruti 800, the defroster switch was grouped with all the extras (rear wiper and washer switch, thats it, it was a ’93 DX model) left and lower of the steering wheel (LHD). I always forgot which was which, and you had to look at it, in that hidden, inconvenient spot, while driving. Suffering from success.
The wavy lines (or some like them) show up on the fog light control also — at least the do on my wife’s PT.
Took me *forever* to figure out what that fog light setting was for — finally had to resort to digging out the owner’s manual.
(Ooops — I guess they’re not wavy, but straight.)
All those ISO standard icons are absolutely *awful* at their supposed job of clearly conveying information without the use of any particular written language. They are terrible, just terrible. It would be better if they were just English words, or hell, Portugese or Ukrainian or even fucking Esperanto or because then at least *some* people would understand them, whereas now they are equally incomprehensible to everyone. In fact, if they’re gonna make everything in cars a touchscreen, there should be an option to replace the stupid symbols with words in the language of your choice.
Those dumb, dumb little symbols. Everyone on ISO Technical Committee ISO/TC 22/SC 39 Ergonomics should be slapped into a coma.
Also, why have a button? Just have them come on for 15 minutes whenever the car starts up, if it’s below say 5°C outside. It’s not like they’re gonna burn out.
It’s a symbol, not a pictogram. So it ought to be related to the symbol for the front defroster. But as a pictogram, it’s 3 devil’s tails. Everybody associates devils with heat, right? It’s 3 devils farting in the direction of the window.
As to where, it ought to be with the control for the front defroster. (Mine is a button in the center of the knob that controls where heater air is directed to.)
I knew a guy who had a circa 1995 Escort that came with a sticker on the console explaining to set the vent to the windshield position and turn on the A/C to defog. Probably a little wordy, and I don’t know how much literacy controls should be assuming, but it was unambiguous in a way a bunch of ikea guys might not be
Re: what the icon on the switch should look like – I think we’re at the stage where folks have come to associate the current, “wrong” but standard, icon with the squiggly arrows with defrosting, so I say keep it. Just like the skeuomorph floppy disk icon meaning Save is likely not going anywhere any time soon, as anachronistic as it has been for decades to anyone not named Jason Torchinsky.
That said, good things happen when Torch thinks established icons suck – I for one have fond memories of an article about the check engine light on the German lighting site – so by all means, Torch, propose a new design!
Re: where the switch should be – thank you for allowing me to Sparkypost once again: I think that the M400 Chevy Spark has the best, most intuitive HVAC/HVAC-adjacent control panel ever – three evenly spaced, equally sized dials that double as buttons. The left one controls the temperature, the middle one controls the intensity, and the right one controls the vents. Pressing down on the left one toggles the AC, the middle one toggles recirculation, and the right one toggles the rear defroster. It’s a brilliant layout and I love it.
All I can see is bacon defroster
If you’re ever bored, like really bored, get a copy of ISO 2575:2021 and look at all of the standardized symbols for (road) vehicle controls.
Interestingly enough, they do have a symbol
for “Windscreen (windshield), electrically heated” but it does not appear that they have one for the rear.
Lets see, here. Just some examples from some of my current/past Fords. A wide variety from a single manufacturer. I have a pair of 2007 Focuses (Foci?), push button with the HVAC controls in the center stack. 1993 Ranger, nope! 2001 Mustang, push button in front of the shifter. 1995 Mustang, under the headlight pull knob. 2002 Windstar, push button with the HVAC controls in the center stack. 1995 & 1997 Aspires, in a row of (mostly unused) switches in the top of the center stack. 1983 Thunderbird, lever in the HVAC controls. I don’t remember the 1978 Fairmont having one. And my 1946 pickup is a rag on the seat!
this is one of those few things that i could get behind automating. determining dew points and measuring temperatures of surfaces is childs play compared to lane keeping and the other garbage thats in cars. it should be tied to the automatic climate control, the rear glass should be kept above a temperature where dew/frost forms. there is no reason to hamper visibility because someone forgot to push a button. im reasonably sure this wouldnt even need additional sensors, as you could measure the resistance and/or current sense the defrost grid, and determine its temperature from it. if you have to have a button, put it on the consolette near the rear view mirror, since thats where you attention is going to be when you notice a problem.