GMC 1994 Yukon Owner's Manual page 145

The air
flow
can be blended between the two positions. To blend between
positions press the side of the button showing the area where you would like
more air flow. The system will automatically begin to blend toward the
position chosen. To stop the system between positions, just press the SAME
side of the button again.
Right Button
Defrost (Top)
:
This setting operates the defroster. Air comes out near the
bottom of the windshield and at your front side windows. Use this setting,
along with a heat setting, when you get fog or ice on the windshield.
Heater (Bottom)
:
Press the bottom of this button and air comes
out
near
the floor. This setting, along with a heat setting, is best for passenger
comfort in cold weather.
The air flow can be blended between the two positions. To blend between
positions press the side of the button showing the area where you would like
more air flow. The system will automatically begin to blend toward the
position chosen. To stop the system between positions, just press the SAME
side of the button again.
A/C Button
Press the button marked A/C to turn your air conditioner on and off. The
A/C symbol will light on your display and air will come out of your
instrument panel vents. The fan will automatically be set on
LOW .
When you press the A/C button to turn the air conditioner off, the system
will operate in the vent mode. When you turn the air conditioner back on,
the system will operate in the mode that you last selected unless the OFF
button was pressed.
MAX Button
If you press the MAX button, the air in your vehicle will be recirculated.
With the air conditioner on, MAX will give you maximum cooling. It can
also be used in all modes to help keep dust out of your vehicle. When MAX
is selected, REC will light on your display.
If your air conditioner develops high system pressure, it will automatically
go into the MAX mode and REC will light on your display. The A/C
system will remain in the MAX mode, even if you press the MAX button,
until system pressure returns to a normal level.
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