Re: E39 Climate Control

["Jim Cash" <j.cash@xxxxxxxxxxxx>]

Tim Wright asks
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I find that on a warm day when the interior temperature rises above 35/40
degreesC,
the climate control ramps the fan up to full speed to reduce the
temperature to the set point. However, it very rapidly turns it back down to
a very slow speed, while the interior temperature is still 10 or so degrees
above the setpoint. The only solution seems to be to adjust the fan speed
manually.
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Tim they do seem to work that way. I understand the blower cuts back to
lower speeds a soon as possible  since noise can sometime be more
objectionable than the warm car. It assumes it will cool shortly - but if
you are feeling hot yourself then I agree it seems that the blower should
stay on high longer.

You do, however have some options you could try.

Since you are (by your address) in the UK your climate control will most
likely be set to "normal".
But there are other software settings - usually called "hot country".  Some
markets (I.E. Gulf States) get the car set to that operation as standard.

You can have yours reset if you wish - and even here there are several
options available.

You can individually set the blower, and .the footwell and defroster vent
flaps to "normal, or "hot country"

As I understand it, setting the blower to hot country causes it to run at a
higher speed longer. I had mine reset and it does seem to be active in
higher speeds longer (and seems to shift speeds much more often than when it
was set to normal.)

Setting he footwell vent flaps, and, or, the  defrost flaps to hot country
causes them to be "partially' open with in A/C mode - thus pushing some air
through those vents as well as the dash front vents.
I had my footwell vents set to hot country to get some cooling down there as
well. Helps a bit but is not significant - could be more.


If you want any changes made you have to go to the dealer and have them put
the car on the DIS system - they can adjust many options - of which the
"Heating/Air Conditioning/Ventilation" is one subset.

Think about this before you do it - it may help, but the changes did not
provide "significant" improvement in my experience.


One thing I noticed is that if you do not have the A/C turned on (just
trying to use cool outside air to cool a warm car) the effect of  engine
heat will raise the temperature of the incoming air through the ducts. At
highway speeds the temp difference is about 2-3 F. But in city traffic it
can be about 5-8F degrees warmer - going as high as 12F higher in stop & go
traffic.  So on days when the outdoor air is OK, you still may need to use
the A/C in the car - especially for a few minutes after getting into a car
that was running but has been parked for a while - the engine heat will have
heat-soaked the entire vent system.
Cheers

Jim Cash

London, Ontario, Canada - Temp here is 88F in the shade this afternoon - and
humid !

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End of bmw-digest V9 #1492
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