Best car heater....to clear windscreen

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Usenet Nutter saying something like:

Still very necessary in some parts of the world - like the Ice Road Truckers' territory. I was somewhat amused to see a large cut-out M for Mack, in the radiator shield. In those kind of temps, there is a very real probablity of the water freezing in the rad if the stat closes down a bit and restricts flow and even when working properly, if the engines on a light load the cold carries away so much heat the cores could freeze. In the recent temps in the British Isles, I would have put a blank over part of the rad on a longer journey.

I popped in to ask a related question and found this. Both my cars (53 Almera 1.8 petrol and 04 Accord 2.0 petrol) have climate control and both have a button to clear the windscreen which: revs the fans; points the heating to the windscreen; sets it to direct flow from the outside (i.e. no recirc); and set the A/C on. Knowledge that A/c should not really run below freezing puts me in a mad flap to switch off the A/C immediately as it switches on.

So my question is if the mechanisms to protect the A/C can be trusted. And, yes, on the Accord I once messed up the A/C cancellation and found out when I got out of the car 8 miles later on hearing it going at the front (not just the light). Indicated -1 springs to mind.

What do folk know about this?

Cheers,

Well even if it didn't work all that happens is that it ices up.

My BMW with climate control does not switch on the AC when you go to defrost. Which is what the setting you've described is called by them. A heated front screen is probably a better option.

So, no irreversible damage? Thanks!

-- Kostas

Your windscreen mists up as there's no air flow, but unless you're exceptionally unlucky that's it.

Depends if that's the only sensor not working.

Thanks. Won't there be hot air flow either?

(Thanks for the warning re other sensors, Dave Plowman.)

Nope, hot & cold air all goes through the evaporator on the way to dry it. Thereagain it'll probably cut out on its own, why do you think it doesn't.

I am not sure I understand your last sentence. If you are asking why I am asking all that, it's because of (mis?)reading the A/C section of the Focus manual (which I no longer have, car or manual :-) ). I was left with the impression that the user needs to ensure that they don't operate the A/C in freezing conditions.

I think I have got it now, thanks for all the inputs.

-- Kostas

You can operate it, it just won't work :-)