Air Con and Outside Temperature

[cordoba lad]

This is starting to bug me now. I know that the air stops working at exterior temperatures below about 3 degree's. Which is a a bit of a pain in the backside when the inside is misted up and its a cold morning. Does or has anyone come across a mod to alleviate the problem, because my mother Yaris can use its Air Con regardless of the outside temperature.

It should in theory be able to be programmed out.

 

[Muttley]

The air cooling system is switched off below about 4°C outside air temperature for two reasons.

1. The air cooling matrix completely fills the inlet air duct, and below 4°C or so any moisture will freeze on the cooling coils. This will block the inlet air pretty quickly, meaning no deisting and no fresh air.

2. Below about 4°C the incoming air is pretty dry anyway. The only reason that "air conditioning" in cars drys the air is that by coooling it, any moisture is squeezed out (cold air can hold less moisture than warm air). The cool air is then heated up, which makes it dry and helps demisting. if the incoming air is already cold, there's not much point in trying to cool it any more.

if you've got a seriously misted up car on freezing mornings and turning on the demist button ( maximum flow to windscreen) doesn't clear it quickly, then you've almost certainly got a water leak and water under the carpets.

Your mum's Yaris is probably switching off the air cooling but not telling our mum about it.

 

[GREY 225]

Its a pain though when its cold and wet and say you get into car wet because of rain the windows start misting up.
All the other cars ive had including corsa, fiesta and even fabia VRS didnt turn air con off when temp fell below 4 oc, the air con was definately working because you can hear the compressor clutch clicking in and out and engine note dropping slightly.
The window demister does get rid of mist but with the air con on it does it so much better.

 

[cordoba lad]

Yes I understand the theory behind why they may want to disable the AC at really cold temperatures.

Trust me there is no water in the car.

What I want to know is does anyone know how to reprogramme the control unit to say 2 degrees because should I need to demist the windscreen at 2 degrees things aren't freezing.