On 12/04/2018 12:21, John Rumm wrote:
On 11/04/2018 23:36, Dave Plowman (News) wrote:
In article ,
*** bert wrote:
On my current car and the last one, the AC would come on when full belt
demist/defrost was selected, then go off again when you went to normal
heating, if the AC was normally off. AC off is marked ECO.

But a small car may not have as sophisticated a system.

My T5 Transporter does that so no reason why a small (or large) car
should not. It also rather cunningly switches the air flow to recycle
when reverse is selected so the exhaust is not sucked into the cab

Wasn't sure how much of it is servo controlled via a computer. Some do
some very clever things. Like keep the fan slow until the engine heats up
enough to give heat, ramp up the speed until the set temperature is
reached, then ramp down to a quiet speed. Some allow individual
control of
either side of the car. And so on.

That's about the only time I use the full auto setting on mine - when
its really cold and I want the fastest possible warm up.


Mine does all that stuff, and I just leave it on auto all the time; it
works so well you never have to touch it apart from to turn on demist.