ice and misting inside C-HR

Not sure if it's because of the current climate but Toyota dealers are a load of rubbish at the moment. About of helpful as a poke in the eye!!

It’s put me off too we were thinking of upgrading to the 2.0 model when the warranty expired but highly unlikely now. Waiting to see what Toyota say next week now.

Not sure i'd rush out to buy any Toyota right now. 

All the models are now too big, too ugly and too expensive. Plus  the days of buy a toyota cos theyre reliable is more or less over, all cars, even the korean cr4p, just tend to work these days.

Do like the Supra though. And that GR Yaris, though not my cup of tea, does seem to have gone down well. Just need a new MR2 and celica now.

I'll say what you probably already know yourself Ash. I've never seen a "sealed" multimedia unit/screen. In fact, generally, nothing "in cab" electronics-wise gets sealed.....in fact far more often than not, nothing electronic-wise, in a "tin box" under bonnet, gets sealed, as such. If you try to seal it, the repeated temperature changes cause repeated pressure changes inside the "sealed box", which will eventually blow a hole in any sealing material. It will then act like a pair of bellows and will suck moisture in, which will then find it difficult to escape.

Going off at a tangent:


Often the box will just be vented (to equalise pressure), with a vent containing some "hydrophobic gauze" (hydrophobic vent):

www.gore.com/gore-protective-vents-for-outdoor-applications-campaign

It produces far less problems long term.


Where stuff (under bonnet again) has tried to be sealed into housings that are "substantial castings", I've seen situations where the casting has been porous (bad casting supplier quality). One design verification test required by at least one vehicle manufacturer, is effectively to dunk the ECU in depth of water for an hour and look for bubbles.


The finished PCB may be conformal coated, to protect against contaminants (like moisture) but again that generally doesn't happen with "in cab" stuff. Conformal coating is a pain in the bum on a high volume electronics' production lines.

(There are reportedly other problems with conformal coating. In countries or places where there are high sulphur content in the air, some reports show the coating acts to "concentrate" the sulphur and actually accelerates electronic component corrosion, compared with not coating it at all. Levels of sulphur corrosion does vary from electronic component (resistors etc) manufacturer to electronic component manufacturer).

As to the "Do these guys think I’m stupid or just gormless?" comment. I suspect they don't think at all. I suspect they are mostly non-technical and effectively are forced to have a "script" and approach which is aimed at the lowest common denominator, customer knowledge and intelligence-wise (Which isn't you!). Very annoying though.

Maybe the misting is normal. Maybe it isn't. I can't help wondering about the fact that the hevac system is now effectively re-humidifying the cabin air after de-humidifying it.

I don't think you'll stop the nav screen "misting" under some conditions.....but stopping it working is perhaps a little more concerning.

I'd still be asking myself if the moisture in the vehicle really was excessive (and if so why) but, no disrespect, I don't think that's ever going to be completely straight-forward for anybody to be completely objective about, without some sort of measurement (i.e. having exactly the same temperature/humidty levels inside and outside one vehicle, compared with another vehicle).

As far as the screen goes, it would have possibly been better if it had failed completely, unfortunately. Then they'd replace.

In the grand scheme of things they won't be too interested. It's not a safety issue. In my opinion, it's very, very, very unlikely to cause say a fire (sorry, thermal event) for example.

If the moisture has provided a conductive path between parts of the electronics, i.e. paths that really shouldn't be there (and it seems to have done, because it stopped working), what it may have done is stressed some of the silicon (chip) device structures slightly, which over time, may lead to the unit failing prematurely (like when it's out of warranty). It may be years away though.

Moisture also has an effect on the printed circuit board (PCB) itself. You can get dendritic growth on the surface of the board and something called "CAF" (Conductive Anodic Filament) on inner layers, if it's a multilayer PCB (many are these days).

www.idc-online.com/technical_references/pdfs/chemical_engineering/The_CAF_Mechanism.pdf

Basically they'll both provided conductive paths, where there shouldn't be and that will eventually produce premature electronics failure. CAF is a real pig. You can't see it and if you're not very careful, it's very easy to destroy the path created, if you go looking for it. There have been recalls with more safety related ECUs, related to CAF. You can mitigate for CAF, at PCB design time.

So saying the moisture has no effect, is garbage, but sorry, your average Mr T dealership/customer services operative won't know any better, but it's not their fault.

At least it's a positive result, Ash. Hope it solves the problem. :TU: