2004 GMC SONOMA air conditioning

A/C (Air Conditioning):Turn the knob to the A/C
position to turn the air-conditioning system on or
off. When the system is on, this setting cools and
dehumidifies the air entering your vehicle and directs it
through the floor outlets as well as the instrument
panel outlets.
MAX A/C (Maximum Air Conditioning):This mode
recirculates much of the air inside your vehicle so
it cools quickly. It directs most of the air through the
instrument panel outlets and a small amount through the
floor outlets.
For quick cool down on hot days, do the following:
1. Select A/C.
2. Select the coolest temperature.
3. Select the highest fan speed.
You may notice a slight change in engine performance
when the air-conditioning compressor shuts off and
turns on again. This is normal. The system is designed
to make adjustments to help with fuel economy while
still maintaining the selected temperature.
The air-conditioning system removes moisture from the
air, so you may sometimes notice a small amount of
water dripping underneath your vehicle while idling
or after turning off the engine. This is normal.Defogging and Defrosting
Fog on the inside of the 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 or frost from your windshield and side windows.
Use the 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. For best results, clear all snow and ice
from the windshield before defrosting.
-(Defog):This mode can be used on cool, humid
days to keep the windshield and side windows clear.
1(Defrost):This mode directs most of the air to the
windshield and the side window outlets, with only a
little air directed to the floor outlets. When you select this
mode, the system runs the air-conditioning compressor
unless the outside temperature is at or below freezing.
Do not drive the vehicle until all the windows are clear.
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Outlet Adjustment
The flow through outlets on your vehicle allow outside
air to enter your vehicle while it is moving. Outside
air will also enter your vehicle while the air-conditioning
compressor is running.
Use the thumbwheels located in the center and on the
sides, to change the direction of the air flowing
through the outlets.
Operation Tips
•
Clear away any ice, snow or leaves from the air
inlets at the base of the windshield that may
block the flow of air into your vehicle.
•Use of non-GM approved hood deflectors may
adversely affect the performance of the system.
•Keep the path under the front seats clear of objects
to help circulate the air inside of your vehicle more
effectively.
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(A) Light Truck (LT-Metric) Tire:The United States
version of a metric tire sizing system. The letter “LT” as
the first two characters in the tire size means a light
truck tire engineered to standards set by the U. S. Tire
and Rim Association.
(B) Tire Width:The three-digit number indicates the
tire section width in millimeters from sidewall to sidewall.
(C) Aspect Ratio:A two-digit number that indicates
the tire height-to-width measurements. For example, if
the tire size aspect ratio is “75,” as shown in item “C” of
the illustration, it would mean that the tire’s sidewall is
75% as high as it is wide.(D) Construction Code:A letter code is used to
indicate the type of ply construction in the tire. The letter
“R” means radial ply construction; the letter “D” means
diagonal or bias ply construction; and the letter “B”
means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:The service description
indicates the load range and speed rating of a tire. The
load index can range from 1 to 279. Speed ratings
range from “A” to “Z”. The light truck tire size example
above shows dual or single tire configurations.Tire Terminology and Denitions
Air Pressure:The amount of air inside the tire pressing
outward on each square inch of the tire. Air pressure
is expressed in pounds per square inch (psi) or
kilopascal (kPa).
Accessory Weight:This means the combined weight
of optional accessories. Some examples of optional
accessories are, automatic transmission, power steering,
power brakes, power windows, power seats, and air
conditioning.
Aspect Ratio:The relationship of a tire’s height to its
width. Light Truck (LT-Metric) Tire
5-64

Fuse Usage
LT TRN Left Turn Signal Rear
RT TRN Right Turn Signal Rear
RR PRK Right Rear Parking Lamps
TRL PRK Trailer Park Lamps
LTHDLP Left Headlamp
RTHDLP Right Headlamp
FRPRK Front Parking Lamps
INT BAT Instrument Panel Fuse Block Feed
ENG I Engine Sensors/Solenoids, MAF,
CAM, PURGE, VENT
ECM B Engine Control Module, Fuel Pump
Module, Oil Pressure
ABS Anti-Lock Brake System
ECM I Engine Control Module Injectors
F/PUMP Fuel Pump
DRL Daytime Running Lamps
A/C Air Conditioning
HORN HornFuse Usage
W/W PMP Not Used
HORN Horn
BTSI Automatic Transmission Shift Lock
Control System
B/U LP Back Up Lamps
IGN B Column Feed,Ignition 2, 3, 4
STARTER Starter
RAP Retained Accessory Power
LD LEV Not Used
OXYSEN Oxygen Sensor
IGN E Engine
MIR/LKS Mirrors, Door Locks
FOG LP Fog Lamps
IGN A Starting and Charging Ignition 1
STUD #2 Accessory Feeds, Electric Brake
PARKLP Parking Lamps
LR PRK Left Rear Parking Lamps
5-99

Capacities and Specications
Please refer toPart E: Maintenance Record on page 6-36in the index for more information. See refrigerant change
label under the hood for charge capacity information and requirements.
ApplicationCapacities
English Metric
Air Conditioning Capacity
Air Conditioning Refrigerant R134a1.8 lbs 0.79 kg
Automatic Transmission
Drain and Refill 5.0 quarts 4.7 L
Cooling System 13.8 quarts 13.1 L
Differential Fluid
Rear Axle
Front Axle4.0 pints
2.6 pints1.9 L4
1.2 L
Engine Oil with Filter 4.5 quarts 4.3 L
Fuel Tank 17.5 gallons 67.4 L
Wheel Nut Torque 100 lb ft 140Y
All capacities are approximate. After refill, the levelmustbe checked.
All capacities are approximate. When adding, be sure to fill to the appropriate level or as recommended in this
manual. SeePart E: Maintenance Record on page 6-36
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Part C: Periodic Maintenance
Inspections
Listed in this part are inspections and services which
should be performed at least twice a year (for instance,
each spring and fall).You should let your dealer’s
service department do these jobs. Make sure any
necessary repairs are completed at once.
Proper procedures to perform these services may be
found in a service manual. SeeService Publications
Ordering Information on page 7-11.
Steering, Suspension and Front
Drive Axle Boot and Seal Inspection
Inspect the front and rear suspension and steering
system for damaged, loose or missing parts, signs of
wear or lack of lubrication. Inspect the power steering
lines and hoses for proper hook-up, binding, leaks,
cracks, chafing, etc. Clean and then inspect the drive
axle boot seals for damage, tears or leakage. Replace
seals if necessary.
Exhaust System Inspection
Inspect the complete exhaust system. Inspect the body
near the exhaust system. Look for broken, damaged,
missing or out-of-position parts as well as open seams,
holes, loose connections or other conditions which
could cause a heat build-up in the floor pan or could let
exhaust fumes into the vehicle. SeeEngine Exhaust
on page 2-29.
Fuel System Inspection
Inspect the complete fuel system for damage or leaks.
Engine Cooling System Inspection
Inspect the hoses and have them replaced if they
are cracked, swollen or deteriorated. Inspect all pipes,
fittings and clamps; replace as needed. Clean the
outside of the radiator and air conditioning condenser.
To help ensure proper operation, a pressure test of
the cooling system and pressure cap is recommended
at least once a year.
6-30