I posted this three weeks ago but it never appeared on my
News Server, although it did appear on Google Groups. But I
didn't receive any responses, so I'll give it one more try.
Does anyone know if the E46 Car/Key memory setting called
"Cooling output", which is set by default to "hot country"
on cars for North America, controls the recirc damper
setting as well as other flaps?
As soon as the AC button is pressed, the intake switches to
recirc, which decreases the airflow to the rear seat area
and also makes the air noise markedly louder.
If the car/key memory is changed to "normal" and this
allowed fresh air to be cooled, these problems would be
eliminated. When getting into a parked hot car, the recirc
button could still be used for rapid initial cooling.
Before I pay the dealer to make the change, I am trying to
get a better idea of what this setting does, besides closing
the footwell and defrost vents.
By removing the cabin air filter, I can see the recirc
dampers closing off the fresh air inlet when the AC button
is pressed, just as they do when recirc is pressed.
I don't understand the problem.
When you get into a hot car and switch the AC on, AND you want max cooling,
you have it because the car has selected it for you. Once the car is cooled,
you switch to normal mode if you want it. You are suggesting that you turn
the system on in Normal, then select Recirc if you want it, then select
Normal again after the car is cooled the way you like it. The car is
demanding a single button press, you are asking for at least two. If
pressing a button is problematic, then the car wants the least number of
button presses already.
Personally, I prefer to ALWAYS make this choice -- Normal or Recirc -- but
if the car made the initial call on what should be selected, a simple button
press would not annoy me.
I live in a temperate climate,and I rarely get into the car
and want max cooling, Jeff. I normally leave the system in
manual mode (floor vents on and face level vents on) with
the fan speed of my choice, to keep the system from blasting
me out of the car with full fan speed. I assume this is
what you mean by normal mode. This isn't Phoenix-weather here!
I didn't mean to imply that I select Recirc manually. I
rarely do, unless following a noxious diesel. The problem
is, as soon as I press the AC button to get additional
cooling, the system goes into recirc and can't be
over-ridden. It simply doesn't matter whether I select
fresh, recirc, or auto recirc.
With the exception of the fixed recirculating air, I get
what I want with a single button-push - AC on or AC off.
That said, I have been out experimenting with the settings
again, and I now find that upping the temperature setting a
few degrees with AC on allows the recirc flaps to open
allowing normal airflow to resume. So I suppose it is
simply a matter of remembering this counterintuitive step
and putting up with slightly warmer footwell air. Whether
the number of degrees I have to add is dependent on the
actual cabin temperature remains to be seen. If I have to
move it up to 80 on a hotter day, I suspect the footwell air
will become much warmer than comfortable even with the AC
on. But this workaround is a help in 70 degree weather.
Jeff Strickland wrote:
Don't know if the e46 system is smart enough to do this, but recent vintage
HVAC systems will switch to recirc mode if the system senses very high cabin
temps. Particularly applicable when starting the car after it's been cooking
in the sun. When the cabin temp then drops far enough the system will allow
the fresh air intake to open.
If, otoh, your e46 is always in recirc mode, even after the cabin has reached
a reasonably cool setting, one can surmise a fault in the controller or one of
the temp sensors could cause the behavior your seeing. That you can see the
actuator moving the damper means the actuator is not the fault, so the problem
is upstream somewhere...
'00 s4 6spd
When it is very hot the AC starts in recirc mode to cool the car down more
quickly. Once the cabin has cooled a bit and you have got moving (so the
ambient air under the bonnet / hood is cooler than it would be if the car
has been standing in the sun, then it will change to external.
Also check you have not got the switch down. Recirc is OK for short
periods, but on a long run the air in the cabin will get stale. I did this
accidentally once after passing a treatment works. 100 miles later I was
nodding off, until I noticed I had left it in recirc by mistake.
Mine does not change to external, no matter how long it has
been running. And it does not respond to the recirc button
when the AC is on and the temperature is set at the minimum.
But I now find if I crank the temperature up a couple of
degrees, the recirc valve reopens. Although this allows a
bit of warm air into the footwell vents it is probably the
closest it will get to acting the way I wanted it to (i.e.
the way all my past cars have acted!)
R. Mark Clayton wrote:
This begs the question - why do you have the temp set to minimum (60F)?
The system can't make more coldness than it's capable of - the only way
it will make the car colder faster is exactly how it's behaving - by
using recirculation to recool already cooled air.
I never change mine from 70F.. and the recirculation works how I would
expect it to.
FWIW - the "hot country" setting doesn't change recirculation mode - it
changes the proportion of cold air sent to the face vents. More is sent
to the face vents since that cold air blowing right on your face gives
you the feeling that it's colder. If you're using manual mode to have
air split between the face vents and foot vents - the "hot country"
setting does absolutely nothing.
And that's how it should be used. Set the temperature to where you want
it to end up and LEAVE IT ALONE - the system is capable of controlling
itself and achieving that temperature without meddling by the driver.
It appears to me that one flaw in the design is that the LED on the recirc
button does not indicate that it is in recirc mode during the max-cooling
periods. The fan speed indicator properly indicates the current fan speed
in Auto mode, why not the Recirc indicator?
And why not allow me to push the recirc button, allowing me to take it out
of recirc mode while leaving the fan in auto mode?
The system is presuming it is more capable of meeting my a/c desires than
it really is.
My question is, if I am willing to put up with a little less
than maximum cooling on a 40C day to get some quiet by not
using recirc, and at the same time get better air paths
through the car, why can't the system accommodate me?
I agree. Manual mode should allow override of everything
Again agreed. How could it possibly know the conditions in
the car better than a human? And how could it know what
makes the human most comfortable in those conditions. There
have been plenty of comments in letters to magazine editors
over the last twenty years bemoaning the loss of the simple
manually controlled heater/AC system. I had a 325 as a
loaner once and was delighted with the simple
'old-fashioned' heater controls.
One of the things I notice is that the a/c in Auto mode overcools A LOT if
the front if the dashboard (the area where the a/c controls are) has been
heated by sunlight coming in throught the sunroof.
The a/c sensors "think" it is much hotter in the car than it really is.
I should have a look at the manual if I were you old chap (RTFM).
If you set the temperature to minimum this has the effect of calling for
maximum cooling (not the ~16C it corresponds to). Maximum cooling is
achieved by recirculating at a fairly high fan speed. Pressing defrost
similarly over-rides various settings on the AC.
So correct operation - no fault found.
Possibly the only car in the world with this I/O error
designed in? Certainly not in any of my previous cars over
the last 25 years. But thank you for answering the non-OP.
I am not talking a huge difference between interior
temperature and ambient. Just a few degrees, perhaps. But
it is often much more comfortable having dehumidified air
coming through the vents. In fact at these small
temperature differences that is more important to me than
the actual cooling.
It seems perfectly normal to me to start off in the morning
with the temp at minimum as I don't want any heat in the
car, and then as the outside temperature rises, press the AC
button for more cooling. Why would I want to increase the
temperature setting at the same time if I want the car to be
The system is automatic - it will produce air at any temperature above 16C
that you select. It won't heat it if you don't want it to. Selecting the
bump stop tells it to do something different - no heating (even if well
below 16C) and maximum cooling including recirculation if the AC is on.
Some cars (like Jag's) have an economy setting, whereby the AC does not
operate [as much] if the incoming air is near the target temperature.
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