Cadillac 2007 DTS Owner's Manual page 209

In order to prevent false temperature readings at
startup, the displayed temperature will not
change until the following occurs:
•
Vehicle speed is above 10 mph (16 kmh) for
5 minutes.
•
Vehicle speed is above 32 mph (51 kmh) for
2 and a half minutes.
The climate control system uses the information
from these sensors to maintain your comfort setting
by adjusting the outlet temperature, fan speed, and
the air delivery mode. The system may also supply
cooler air to the side of the vehicle facing the sun.
The recirculation mode will also be used as needed
to maintain cool outlet temperatures.
Defogging and Defrosting
Fog on the inside of windows is a result of high
humidity (moisture) condensing on the cool window
glass. This can be minimized if the climate
control system is used properly. There are
two modes to clear fog from your windshield.
Use the floor/defog mode to clear the windows
of fog or moisture and warm the passengers. Use
the defrost mode to remove fog or frost
from the windshield more quickly.
W
(Floor/Defog): Turn the control to this mode
to direct approximately half of the air to the
floor outlets and the remaining air is directed to
the side window outlets and to the windshield.
When you select this mode, the system turns off
recirculation and runs the air conditioning
compressor unless the outside temperature is at
or below freezing. The recirculation mode
cannot be selected while in the floor/defog mode.
0
(Defrost): Turn the control to this mode to
direct most of the air to the windshield and the side
window outlets. In this mode, the system will
automatically turn off recirculation and run the air
conditioning compressor, unless the outside
temperature is at or below freezing. Recirculation
cannot be selected while in the defrost mode. Do
not drive the vehicle until all the windows are clear.
For professional vehicles, air will be allowed to flow
through the rear outlets. For quicker defrost, press
the AUX button on the front climate control system
so that the light is not lit.
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