[JVFan]

Why does the AC come on when you set the climate control to auto even if it is below freezing?

[natalia]

Did you turn that little nob to the red? it's on the center console. I don't know if this will help or not, but it's worth a shot.

[JVFan]

Which knob?

[natalia]

I think it's right in the middle under the center vents. It's not really a knob, it looks like the vent controls slider thing, but it goes side to side, instead of up and down.

[deutsch100]

Even if it's below freezing the AC compressor will act as a whole car defroster. The stupidest thing anyone does is use the heat alone when it is cold out...the windows will fog up, and it looks like you are driving some old car..or are stupid to not know to use AC with Auto

[JVFan]

Originally Posted by deutsch100

Even if it's below freezing the AC compressor will act as a whole car defroster. The stupidest thing anyone does is use the heat alone when it is cold out...the windows will fog up, and it looks like you are driving some old car..or are stupid to not know to use AC with Auto

You obviously live in a warm climate...there are days when the relativity is so low and the air temp is so cold that running the AC is stupid.

[deutsch100]

Even when we are in Germany and Sweden (very, very cold in Winter, trust me!) with our families, keeping the system on Auto with the snow flake illuminated is the best way. Pretty sure the manual says so too, as does BMW recommend. It works amazing. Hope this helps!

[JVFan]

Fuel consumption goes down though...combine that with cold driving and city driving and that must amount to terrible MPG.

[Squawks]

Do you actually have firsthand or technical specifications for the fuel consumption of using the a/c? I'm actually more concerned about running my refridgerant dry rather than fuel.

As per your information, I personally did a statistical analysis on the rates of fuel consumption on or off. There is negligible difference. Again, like I said, I'm more concerned about wear/tear on the A/C system itself.

[Compos Mentis]

Originally Posted by deutsch100

Even when we are in Germany and Sweden (very, very cold in Winter, trust me!) with our families, keeping the system on Auto with the snow flake illuminated is the best way. Pretty sure the manual says so too, as does BMW recommend. It works amazing. Hope this helps!

My Honda would let you put on heat and A/C at the same time, but my Ford Explorer would not. After awhile, the windows do fog up. In the Honda, hit the A/C for awhile, and it clears right up! It's not just really cold areas. I believe this is just one more reason US auto makers are in so much trouble.
(The Honda would also kick off the A/C momentarily if you had to floor it. That was great.)
CM

[ksfrogman]

Originally Posted by Compos Mentis

My Honda would let you put on heat and A/C at the same time, but my Ford Explorer would not. After awhile, the windows do fog up. In the Honda, hit the A/C for awhile, and it clears right up! It's not just really cold areas. I believe this is just one more reason US auto makers are in so much trouble.
(The Honda would also kick off the A/C momentarily if you had to floor it. That was great.)
CM

On my Supra, I did have to manually press the AC button while defrosting, but on MY Ford Explorer, the defroster turns the AC compressor on automatically as it does dry up the air. It simply doesn't have a light indicating that it's doing that.

[voltron1011]

Your fuel consumption will be negligible with AC on during winter months. Even though the AC button is on that doesn't mean the compressor is actually engaged. The compressor engages based on a pressure switch inside the AC plumbing. Once the switch reaches a predetermined temp, it switches the AC off. This also takes into account humidity because the condensor takes water vapor from the air. The compressor will kick on just long enough to remove any humidity (even if it is -3 outside) from the air. This is why your windows won't fog up and your fuel consumption won't be affected.

[Compos Mentis]

Originally Posted by ksfrogman

On my Supra, I did have to manually press the AC button while defrosting, but on MY Ford Explorer, the defroster turns the AC compressor on automatically as it does dry up the air. It simply doesn't have a light indicating that it's doing that.

I have to try that! Thanks! (I still don't like US cars anymore... )
What year is your explorer? Mines a '96.

[JVFan]

Originally Posted by voltron1011

Your fuel consumption will be negligible with AC on during winter months. Even though the AC button is on that doesn't mean the compressor is actually engaged. The compressor engages based on a pressure switch inside the AC plumbing. Once the switch reaches a predetermined temp, it switches the AC off. This also takes into account humidity because the condensor takes water vapor from the air. The compressor will kick on just long enough to remove any humidity (even if it is -3 outside) from the air. This is why your windows won't fog up and your fuel consumption won't be affected.

Well done Voltron...nice info!

[CPTHALL]

I asked the dealer the same thing and he said it controls the humidity within the car.

[rightnow]

AC button should always be active, even in the winter! Many people stop using the AC in the winter, and after a few years, when the first summer day appears, your AC will break if not used once in a while. I dont know how to phrase it in english, but my dealer told me to have it on always. And my company that sells other types of cars are recommanding this too. (Sweden)

[Bimmerista]

Originally Posted by JVFan

You obviously live in a warm climate...there are days when the relativity is so low and the air temp is so cold that running the AC is stupid.

Not stupid-the Ac serves as a dehumidifier in winter.

[dbstang]

My 2 cents. I beleive why the AC is on during cold weather is the the heating system uses the heat generated by the compressor to get heat into the passanger compartment sooner than waiting for the water to heat up.

Pretty sure that's how it woks.

[beri486]

I don't turn on Auto at all when it's cold outside. I use the fan control lever below the temperature LED panel to get the fan going and turn the knobs to a comfortable temprature. It seem to work nicely and no fog developes.
So the temp. control works even if you don't turn AUTO on, at least for heat. Will doing this damage the CC system?

[driverseven]

I have been very impressed with the car's ability to control climate -- just dial the temperature up or down and it does a great job.

Only when it is extremely cold -- like when it was 5 degrees F (that's -15C) the other day -- will I click off the recirculation for the first few minutes to get the car warm faster.


my last BMW (a 2000 528) was nowhere near as effective. I was always fiddling with the controls.