2002 GMC YUKON DENALI fog light

2-40
This procedure applies only to vehicles first sold in the
United States.
When necessary, you may turn off the automatic
headlamp system and the Daytime Running Lamps
(DRL) feature by following these steps:
1. Turn the ignition to RUN.
2. Press the DOME OVERRIDE button four times
within six seconds. After the fourth press of the
button, a chime will sound informing you the system
is off.
3. The system will revert back to the automatic mode
when the DOME OVERRIDE button is again pushed
four times within six seconds (a chime will sound),
or when the ignition is turned off and on again.
When the system is turned off, the headlamps will not
automatically come on when it becomes dark outside.
As with any vehicle, you should turn on the regular
headlamp system when you need it.
Fog Lamps
Use the fog lamps for better vision in foggy or misty
conditions. Your parking lamps and/or low
-beam
headlamps must be on for your fog lamps to work.
The fog lamp button is
located on the left side of
the instrument panel.
Press the button to turn the fog lamps on while the
headlamps are on. Press the button again to turn them
off. An indicator light will glow near the button when
the fog lamps are on.
Remember, fog lamps alone will not give off as much
light as your headlamps. Never use your fog lamps in
the dark without turning on your headlamps.
The fog lamps will go off whenever your high
-beam
headlamps come on. When the high beams go off, the
fog lamps will come on again.
The fog lamps will be cancelled after the ignition is
turned off. If you still want to use the fog lamps after
you restart the vehicle, you will need to press the fog
lamp button again.

3-4
(Recirculation): Press this button to limit
the amount of outside air entering the vehicle to a very
small amount. This setting helps limit odors entering the
vehicle and will assist in reaching a comfortable
temperature in very hot temperature conditions.
Pressing recirculation will cause the system to
recirculate interior air continuously and may cause the
vehicle windows to fog if the passenger compartment
floor is excessively wet.
A/C (Air Conditioning): Press this button to turn
the air conditioning on and off. The system will cool and
dehumidify the air inside the vehicle when the A/C light
is on. When in AUTO, the A/C is automatically engaged
when necessary.
Air conditioning will be automatically disabled when
the outside temperature drops below a level at which
air conditioning is effective.Pressing the recirculation button will cancel outside air
operation. To return to normal system operation and to
prevent stale passenger compartment air, be sure to
return to the outside air position.
To help reduce window fogging, recirculation will not
be available in floor, blend or defrost modes. If the
recirculation button is pressed in these modes, the LED
indicator for recirculation will flash three times
indicating that forced outside air is activated and
recirculation is not available.
If the air conditioning system is activated and system
demand is high in situations such as city traffic, idling,
or very hot weather, the system will automatically
switch from outside air to recirculation. The LED
indicator will not change. After demand on the system is
reduced, the system will return back to outside air.

3-5
Mode Knob - Automatic Operation
When the system is set in AUTO mode, sensors will
control the air delivery mode. Air will come primarily
from the floor or instrument panel outlets, with some air
directed to the windshield to prevent fogging.
When the system is in AUTO mode, the air conditioning
light will turn on, and the recirculation and outside air
lights will turn off. With the system in full automatic
control (both the fan and mode knobs in AUTO), you
still have the ability to override any function. However,
continually overriding the outside air or the A/C
compressor will limit the ability of the system to cool
the vehicle quickly.
If you push a button for a function which is not
available, the light next to that button will flash three
times to alert you that it's not available.
To find your comfort zone, start with the 74
F (23
C)
setting and allow about 20 minutes for the system to
adjust the temperature if necessary.With the automatic setting, the air conditioning
compressor automatically cycles when needed to cool
the air. In cold weather, when the system senses the
need for heat, the airflow will be directed out the floor
outlets. As the interior temperature approaches a desired
setting, the fan speed will decrease. To maintain interior
comfort, the airflow will adjust between the instrument
panel outlets and floor outlets. On bright sunny days
in cool weather, the airflow may come out of the
instrument panel and the floor outlets (bi
-level mode)
to maintain comfort and prevent stuffiness.
To avoid blowing cold air in cold weather, the system
will delay turning on the fan until warm air is available.
The length of delay depends on the outside air
temperature, engine coolant temperature or the time
since the engine was last started. As the coolant
warms up, the fan speed will gradually increase and
air will flow from the floor outlets, with some airflow
to the windshield to prevent fogging under most
normal conditions.
Be careful not to put anything over the solar sensor
located near the center of the instrument panel.
This sensor is used by the automatic system to
regulate temperature.

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Name Usage
B/U LP Backup Lamps, Automatic
Transmission Shift Lock
Control System
ATC Automatic Transfer Case
RR DEFOG Rear Window Defogger, Heated
Mirrors (Relay)
RTD Autoride
(Real Time Damping)
RR PRK Right Rear Parking Lamps
ECM B VCM/PCM
F/PMP Fuel Pump (Relay)
O2 A Oxygen Sensors
O2 B Oxygen Sensors
LR PRK Left Rear Parking Lamps
RR DEFOG Rear Window Defogger, Heated
Mirrors
HDLP Headlamps (Relay)
TRL PRK Parking Lamps Trailer Wiring
PRIME Not UsedName Usage
RT HDLP Right Headlamps
DRL Daytime Running Lamps (Relay)
HTD MIR Heated Mirrors
LT HDLP Left Headlamps
A/C Air Conditioning
AUX PWR Cigarette Lighter, Auxiliary
Power Outlets
SEO 2 Special Equipment Option Power,
Power Seats
SEO 1 Special Equipment Option Power
DRL Daytime Running Lamps
A/C A/C (Relay)
FOG LP Fog Lamps
FOG LP Fog Lamps (Relay)
RADIO Audio System, Instrument Cluster,
Climate Control System
CIGAR Cigarette Lighter, Auxiliary
Power Outlets