Hummer 2004 H2 - Manual (Page 157)

If the driver’s and passenger’s temperature settings are
the same when AUTO is pressed, the temperature setting
and both arrows will be displayed for five seconds along
with the automatic air delivery mode and fan speed. After
the five second update, the display will change to show
the temperature setting, both arrows and AUTO.
Air Conditioning
#
(Air Conditioning): Press this button to turn the air
conditioning (A/C) compressor on and off. The
snowflake symbol will appear on the display when the
A/C is on.
Pressing this button when the outside temperature is too
cool for air conditioning to be effective will make the
snowflake symbol flash three times and then turn off to let
you know that the air conditioning mode is not available. If
the air conditioning is on and the outside temperature
drops below a temperature which is too cool for air
conditioning to be effective, the snowflake symbol will
turn off to let you know that the air conditioning mode has
been canceled.
^ (Air Conditioning Off): On some vehicles, when
you turn the air conditioning off, this symbol will appear
on the display. If your vehicle does not have this
symbol, the snowflake symbol will turn off to let you
know the air conditioning is off.
When air conditioning is selected or in AUTO mode, the
system will run the air conditioning automatically to
cool and dehumidify the air entering the vehicle. If you
select A/C off while in front defrost, defog or
recirculation, the A/C snowflake symbol will turn off, but
the A/C compressor will still run to help prevent
fogging.
On hot days, open the windows long enough to let hot
inside air escape. This reduces the time it takes for
your vehicle to cool down. Then keep your windows
closed for the air conditioner to work its best.
On cool, but sunny days while using manual operation
of the automatic system, use bi-level to deliver warm
air to the floor and cooler air to the instrument
panel outlets. To warm or cool the air delivered, turn the
temperature knob to the desired setting.
In AUTO mode the system will cool and dehumidify the
air inside the vehicle. Also while in AUTO mode, the
system will maximize its performance by using
recirculation as necessary.
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