Air conditioning light

On some cars the aircon is automatically switched on, to dry the air, if the heater/blower is set to clear the windscreen rather than to blow/hot/cool air into the passenger space.

No idea but it may be a menu setting (possibly only available with servicing equipment) rather than a fault.

Makes the car cooler in summer makes the demister work better in winter

Must use more fuel ultimatly, but I still keep the AC on most of the time.

Scott wrote on 11/04/2018 :

My climate system default to on, or rather enabled when the ignition is cycled. Even when not needed for cooling it can keep the air in the car drier, than it would be. It is especially useful for clearing a misted screen in damp weather.

If you leave the heater controls set to "auto" - then you may find it selects AC as and when it thinks it needs it to meet the requested temperature, or when demisting is required.

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.

Perhaps its to ensure the AC is used regularly to prevent the common faults due to seals drying out when AC is not used for months.

Mike

Most switch on when you use fast de-frost, etc. Which you almost will do in the winter months when you may not need to cool the interior. Which should keep it happy.

In article , "Dave Plowman (News)" writes

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

In article , "Dave Plowman (News)" writes

Which is contradiction to your post a short while ago. Had time to look it up and realise how wrong you where? (Again)

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.

Do get a grip, Bert. I have two cars both with AC, one newish, one old. They are very different.

If it is so it is a dumb design. A/C on in any car takes a fair bit of drive power, the car slows down. In a car like Nissan Micra which I think is of 1600 or 1400 cc it would mean engine would struggle to move with even an additional passenger on board. I would investigate, make it default A/C +off condition

Given that you clearly have no experience, why make stuff up?

I?ve driven plenty of small hire cars with A/C that manage just fine, even with extra passengers.

Tim

Have you ever driven a car with a 1400/1600cc size engine or any car with A/C ?

One possibility and I dont know that car, is that you set the heater to demist: On mine that automagically puts the aircon on to dry the air.

Depends what you mean by fine. All AC takes quite a bit of power to drive it and that power has to some from somewhere.

Thanks for all the helpful replies. Such level of sophistication had not occurred to me. I will need to explore thoroughly. It's certainly different to my previous Micra.

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.