Page 257 of 331
6-62
Fuse/Circuit
BreakerUsage
1 Stop/TCC Switch, Buzzer,
Center High Mounted Stop Lamp,
Hazard Lamps, Stoplamps
2 Not Used
3 Courtesy Lamps, Cargo Lamp,
Glove Box Lamp, Dome/Reading
Lamps, Vanity Mirrors
4 Instrument Cluster, DRL Relay,
Lamp Switch, Keyless Entry,
Low Coolant Module,
Illuminated Entry Module,
DRAC (Diesel Engine)
5 Not Used
6 Cruise Control
7 Auxiliary Power Outlet
8 Crank
Page 258 of 331
6-63
Fuse/Circuit
BreakerUsage
9 License Lamp, Parking Lamps,
Taillamps, Roof Marker
Lamps, Front Sidemarkers,
Door Switch Illumination,
Headlamp Switch Illumination
10 Not Used
11 Wiper Motor, Washer Pump
12 A/C, A/C Blower,
High Blower Relay
13 Power Amp, Cigarette Lighter,
Door Lock Relay
14 Cluster, Comfort Controls,
Instrument Switches, Radio
Illumination, Chime Module
15 DRL Relay
16 Front and Rear Turn Signals,
Back
-Up LampsFuse/Circuit
BreakerUsage
17 Radio (Ignition)
18 4WAL/VCM, Antilock Braking
System, Cruise Control
19 Radio (Battery)
20 PRNDL, Automatic Transmission,
Speedometer, Check Gages
Warning Light
21 Security/Steering
22 Not Used
23 Not Used
24 TP2 Relay (Gasoline Engine)
A Power Door Lock, Keyless
Entry Module
B Power Windows
Page 259 of 331
6-64
Underhood Fuse Block
The underhood fuse block is located in the rear of the
engine compartment near the brake fluid reservoir.
See ªEngine Compartment Overviewº in the Index
for more information on location. Move the retainer
clips for the cover to access the fuse block.
You can remove fuses with a fuse extractor which is
mounted to the interior fuse block. To remove fuses
if you don't have a fuse extractor, hold the end of the
fuse between your thumb and index finger and pull
straight out.
Name Usage
Starter Relay Starter
A/C Relay Air Conditioning
Fuel Pump Relay Fuel Pump
Brake Lamp
RelayBrake Lamp
Blank Not Used
Page 260 of 331
6-65
Name Usage
Horn Relay Horn
ECM
-B Fuel Pump, PCM/VCM
RR DEFOG Not Used
IGN
-E A/C Compressor Relay,
Dual Tanks
Blank Not Used
Blank Not Used
Blank Not Used
HORN Horn, Underhood Lamps
AUX FAN Not Used
ECM
-1 Injectors, PCM/VCM, Fuel
Solenoid (Diesel Engine) Fuel
Control Module (Diesel Engine)
HTD ST
-FR Not Used
Blank Not Used
Blank Not Used
A/C Air Conditioning
PTO PTO RelayName Usage
ENG
-1 Ignition Switch, Exhaust Gas
Recirculation, Canister Purge,
EVRV Idle Coast Solenoid, MAF,
Heated O
2, Fuel Heater (Diesel
Engine), Water Sensor (Diesel
Engine), Boost Solenoid (Diesel
Engine), EPR (Diesel Engine)
HTD ST
-RR Not Used
Blank Not Used
Diode Not Used
LIGHTING Headlamp and Panel Dimmer
Switch, Fog and Courtesy Fuses
BATT Battery, Fuse Block Busbar
IGN A Ignition Switch
IGN B Ignition Switch
ABS Anti
-Lock Brake Module
BLOWER High Blower Relay
STOP/HAZ Stoplamps
HEATED
SEATSNot Used
Page 261 of 331
6-66
Replacement Bulbs
Lamps Quantity Number
Sealed Beam Headlamps 2 H6054
Front Marker Lamp 2 194
Front Parking and Turn Lamp 4 2357NA
Rear Parking Lamp 2 3057
Rear Stop and Turn Lamp 2 3057
Back
-up Lamp2 3156
Roof Marker Lamps 5 194
For any bulb not listed here, contact your dealer.
Capacities and Specifications
All capacities are approximate. When adding, be sure
to fill to the appropriate level or as recommended in
this manual.
Please refer to ªRecommended Fluids and Lubricantsº
in the Index for more information.
Engine TypeVIN
CodeSpark Plug
Gap
ªVORTECº 8100 V8 G 0.060 inches
(1.52 mm)
Wheels and Tires
Model Description Torque
Front 5 bolts (5/8 in.)
175 lb
-ft (240 N´m)
Rear 10 bolts (5/8 in.)
175 lb
-ft (240 N´m)
Tire Pressure See the Certification/Tire label on the
rear edge of the driver's door or the
incomplete vehicle document in the cab.
Page 262 of 331
6-67 Capacities
After refill, the level must be rechecked. See ªCooling
Systemº in the Index.
Engine VIN Quantity
ªVORTECº 8100 G 28.5 quarts (27.0 L)
Engine Oil with Filter
After refill, the level must be rechecked. Add enough
engine oil so that the fluid is within the proper operating
range. See ªEngine Oilº in the Index.
Engine VIN Quantity
ªVORTECº 8100 G 6.6 quarts (6.3 L)
Fuel Tank Capacity
Type Quantity
Front Tank 22.0 U.S. gallons (79 L)
Rear Tank 18.0 U.S. gallons (68 L)
Air Conditioning
Refrigerant Capacity
If you do your own service work, you'll need the proper
service manual. See ªDoing Your Own Service Workº in
the Index for additional information. It is recommended
that service work on your air conditioning system be
performed by a qualified technician.
Air Conditioning
Refrigerant R
-134a 2.0 lbs (0.91kg). . . . . . . . . . . . .
Use Refrigerant Oil, R134a Systems
Page 263 of 331

6-68
Normal Maintenance
Replacement Parts
Replacement part numbers listed in this section are
based on the latest information available at the time of
printing, and are subject to change. If a part listed in
this manual is not the same as the part used in your
vehicle when it was built, or if you have any questions,
please contact your GM truck dealer.
These specifications are for information only. If you
have any questions, see the service manual for the
chassis or refer to the body manufacturer's publications.VIN Code G. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Filter* PF454. . . . . . . . . . . . . . . . . . . . . . . .
Engine Air Cleaner Filter* A1300C . . . . . . . .
Spark Plugs*** TJ14R-P15 . . . . . . . . . . . . . . .
Fuel Filter* GF626. . . . . . . . . . . . . . . . . . . . . . .
Wiper Blades** 22154886. . . . . . . . . . . . . . . . .
Wiper Blade Type Trico. . . . . . . . . . . . . . . . . .
Wiper Blade Length 18 inches (45.0 cm). . . . . .
*ACDelco
part number
**GM part number
***Denso part number
A1301C high
-capacity air cleaner filter.
Page 264 of 331
7-
7-1
Section 7 Maintenance Schedule
This section covers the maintenance required for your vehicle. Your vehicle needs these services to retain its safety,
dependability and emission control performance.
7
-2 Introduction
7
-4 Part A: Scheduled Maintenance Services
7
-8 Short Trip/City Scheduled Maintenance
7
-30 Long Trip/Highway Scheduled Maintenance7
-44 Part B: Owner Checks and Services
7
-49 Part C: Periodic Maintenance Inspections
7
-51 Part D: Recommended Fluids and Lubricants
7
-54 Part E: Maintenance Record