Temps here in the northeast are wintry cold which begs the question - how come the "Auto" setting on the climate system defaults to air conditioning?! I set my desired temperature to 74, start the car, and it blows lots of cold air my way. The front and rear defrosters are not turned on, which could understandably trigger the AC. Photo attached.

 

The AC light indicates that the system is 'armed' only and not necessarily active. The compressor will be turned on if the OAT is warm enough to help reduce humidity inside the car.

If auto is selected the fan should only blow if air of the desired temp is available.

 

As I understand from my X-Type (looking for an XJ) if you set the climate control is auto and at given temp, it will run because the temp sensor feel cold so it try to blow the air in but unfortunately the engine is not warm up, and cold air is come in the cabin, it not the air from the air condition, once the engine warm up the inside temp reach the set temp, it will blowing the warm air and the fan will stop, but automatic turn on occasional if the temp was lower down, so turn it off when you start the car cold and wait till the temp gauge move up and turn it on. in the summer A/C make the cool air quicker, so you don't see it blow much the hot air.

 

My car has roughly the same CC (climate control) system but I'm not sure it does the same - if I understood you.

You might check each of the internal sensors are OK. (E.g. they can get a film of dirt/etc - which may clean off - or just plain fail.)

My CC seems to blow air once it can provide it warmer than the internal sensors say the car is.

 

I agree with Mikey. It's to dehumidify the air.

My X300 always defaulted to an 'armed' compressor circuit even when heating was called for....and the system did whatever is does to determine when and how long the compressor should actually be engaged. This capability could be defeated and quite often the result was the windows fogging up...proving the effectiveness of the system.

Older Jags had less intelligent climate controls and the compressor was simply engaged whenever the climate control was in use, period. All incoming air was first chilled and dehumidified and then heated as needed.

In the grand scheme of things it is common on for the compressor to run, or to be capable of running, even when heat is called for.

More surprising is your remark about getting cold air in the face, when heat is called for, after starting the car. All my Jags (and many other cars) were designed such that, when heating was called for, the blowers would not operate at all *until* the engine coolant was warm enough to actually provide warm air.

Cheers
DD

 

Greg,

To prove what Mikey and Doug have reported, just turn you system to manual heat with the A/C off and watch the insides of your windows fog up.

Cheers,

Don

 

I know we don't get such cold weather as some areas over there but in nearly 30 years of Jaguar ownership I have never over ridden the air con auto setting.
As mentioned above, in the winter months it acts as a dehumidifier to keep the windows from misting up.

 

Three of my cars have an 'auto' setting for the HVAC. Aside from the occasional temporary override for clearing the windscreen, 'auto' is selected year round.

I let the car figure out if the AC should run or not.

 

My other car has A/C but selection is purely manual. I find I use of it much more in the winter, to prevent misting on the windscreen, than I do in the summer for comfort.

The Jag I just leave in auto.

 

The air-con part of the climate control works above a fixed, above-freezing point, temperature to avoid icing on the evaporator.

On climate control systems, provided the ambient temperature is above freezing, it will cool the air before it gets heated to the temperature set by the driver. This removes the excessive vapour in the air and stops windows misting up either summer or winter.