2004 CHEVROLET SILVERADO turn signal

Heavy-DutyTrailer Wiring
Harness Package
Your pickup may be equipped with the eight-wire trailer
towing harness. This harness with a seven-pin
universal trailer connector is attached to a bracket on
the hitch platform.
* The Center High-Mounted Stoplamp (CHMSL) wire is
tied next to the trailer wiring harness for use with a
trailer, slide-in camper or cap.The eight-wire harness contains the following
trailer circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Light Blue: CHMSL
Red: Battery Feed
Dark Blue: Trailer Brake
If your trailer is equipped with electric brakes, you can
get a jumper harness (electric trailer brake control)
with a trailer battery feed fuse from your dealer.
If you need to tow a light-duty trailer with a standard
four-way round pin connector you can also get an
adapter from your dealer.
4-96

Camper/Fifth-Wheel Trailer Wiring Package
The eight-wire camper harness is located under the
front edge of the pickup box on the driver’s side of the
vehicle, attached to the frame bracket. A connector
will have to be added to the wiring harness which
connects to the camper.
The eight-wire harness contains the following
camper/trailer circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Light Blue: Center High-Mounted
Stoplamp (CHMSL)
Red: Battery Feed
Dark Blue: Trailer BrakeIf your vehicle is equipped with the “Heavy-Duty
Trailering” option, please refer to “Heavy-Duty Trailer
Wiring Package” earlier in this section.
When the camper-wiring harness is ordered without the
heavy-duty trailering package, an eight-wire harness
with a seven-pin connector and separate CHMSL
connector are located at the rear of the vehicle and are
tied to the vehicle’s frame.
4-97

Service............................................................5-3
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
Your Vehicle..............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-6
California Fuel...............................................5-6
Additives.......................................................5-7
Fuel E-85 (85% Ethanol).................................5-8
Fuels in Foreign Countries...............................5-9
Filling Your Tank............................................5-9
Filling a Portable Fuel Container.....................5-11
Checking Things Under the Hood....................5-12
Hood Release..............................................5-12
Engine Compartment Overview.......................5-14
Engine Oil...................................................5-20
Engine Air Cleaner/Filter................................5-25
Automatic Transmission Fluid
(Except Allison Transmission
®) ....................5-27
Automatic Transmission Fluid
(Allison Transmission
®) ...............................5-30
Manual Transmission Fluid.............................5-33
Hydraulic Clutch...........................................5-34Engine Coolant.............................................5-35
Coolant Surge Tank Pressure Cap..................5-38
Engine Overheating.......................................5-38
Cooling System............................................5-41
Engine Fan Noise.........................................5-46
Power Steering Fluid.....................................5-46
Windshield Washer Fluid................................5-47
Brakes........................................................5-49
Battery........................................................5-52
Jump Starting...............................................5-53
All-Wheel Drive..............................................5-58
Rear Axle.......................................................5-59
Four-Wheel Drive............................................5-60
Noise Control System.....................................5-61
Tampering with Noise Control System
Prohibited.................................................5-61
Bulb Replacement..........................................5-63
Halogen Bulbs..............................................5-63
Headlamps..................................................5-63
Front Turn Signal, Sidemarker and
Daytime Running Lamps.............................5-65
Roof Marker Lamps......................................5-66
Center High-Mounted Stoplamp (CHMSL)
and Cargo Lamp.......................................5-68
Section 5 Service and Appearance Care
5-1

Front Turn Signal, Sidemarker and
Daytime Running Lamps
A. Sidemarker Lamp
B. Retainer Clip
C. Front Turn Signal Lamp
D. Daytime Running Lamp
1. Remove the headlamp assembly as mentioned
previously.2. Press the retainer clip, located behind the turn
signal housing, towards the outside of the vehicle.
3. Pull the turn signal housing out from the vehicle.
4. Press the locking release lever, turn the bulb socket
counterclockwise and remove the socket from the
turn signal housing.
5. Remove the old bulb from the bulb socket.
6. Put the new bulb into the bulb socket. Use care not
to touch the bulb with your ngers or hands.
7. Put the bulb socket into the turn signal housing and
turn it clockwise until it locks.
8. Reinstall the turn signal housing onto the vehicle,
placing the hook and posts on the inner side into
the alignment holes, and the outer side into
the retainer bracket. Push until you hear a click.
9. Reinstall the headlamp assembly.
5-65

Taillamps
1. Open the tailgate.
2. Remove the two rear
lamp assembly screws
near the tailgate
latch and pull out the
lamp assembly.Your vehicle may have one of the following
taillamp assemblies:
A. Stoplamp
B. Turn Signal
C. Back-up Lamp
A. Stoplamp
B. Turn Signal Lamp
C. Back-up Lamp
D. Side Marker Lamp
5-70

Taillamps (Chassis Cab Models)
A. Turn Signal Lamp
B. Stoplamp
C. Back-up Lamp
1. Using your hands, peel the rubber seal away from
the lens.
2. Lift the lens off the lamp assembly.
3. Pull the old bulb straight out from the socket.
4. Put a new bulb into the socket and press it in until it
is tight.
5. Reinstall the lens and the lens seal.
Replacement Bulbs
Exterior Lamp Bulb Number
Low-Beam Headlamps 9006
High-Beam Headlamps 9005
Daytime Running Lamps (DRL) 4114K
Front Roof Marker Lamps 194
Front Parking and Turn Lamp 3457A
Rear Marker Lamp, Taillamp and
Stop Lamp**3157
Taillamp and Stop Lamp** 1157
Sidemarker Lamp (If Equipped) 194
Rear Turn Lamp 3157
Rear Turn Lamp ** 1156
Back-up Lamp 3157
Back-up Lamp** 1156
Center High-Mounted Stoplamp 912
Cargo Lamp 912
Fender Marker Lamps 194
* For any Bulb not listed here, contact your dealer.
** Chassis Cab Models
5-72

Fuses Usage
IGN 3 Ignition, Heated Seats
4WDFour-Wheel Drive System,
Auxiliary Battery
HTR A/C Climate Control System
LOCK (Relay)Power Door Lock Relay
(Lock Function)
HVAC 1 Climate Control System
L DOORDriver’s Door Harness
Connection
CRUISECruise Control, Power Take
Off (PTO)
UNLOCK (Relay)Power Door Lock Relay
(Unlock Function)
RR FOG LP Not Used
BRAKE Anti-Lock Brake System
DRIVER UNLOCKPower Door Lock
Relay (Driver’s Door
Unlock Function)
IGN 0 TCM
TBC IGN 0 Truck Body Controller
VEH CHMSLVehicle and Trailer High
Mounted Stoplamp
LT TRLR ST/TRN Left Turn Signal/Stop TrailerFuses Usage
LT TRNLeft Turn Signals
and Sidemarkers
VEH STOPVehicle Stoplamps, Brake
Module, Electronic Throttle
Control Module
RT TRLR ST/TRN Right Turn Signal/Stop Trailer
RT TRNRight Turn Signals
and Sidemarkers
BODY Harness Connector
DDM Driver Door Module
AUX PWR 2 Not Used
LOCKS Power Door Lock System
ECC Not Used
TBC 2C Truck Body Controller
FLASH Flasher Module
CB LT DOORSLeft Power Windows
Circuit Breaker
TBC 2B Truck Body Controller
TBC 2A Truck Body Controller
5-125

Fuses Usage
4WSVent Solenoid
Canister/Quadrasteer
Module Power
RR HVAC Not Used
AUX PWRAuxiliary Power
Outlet — Console
IGN 1 Ignition Relay
PCM 1 Powertrain Control Module
ETC/ECMElectronic Throttle Control,
Electronic Brake Controller
IGN EInstrument Panel Cluster, Air
Conditioning Relay, Turn
Signal/Hazard Switch,
Starter Relay
RTD Ride Control
TRL B/U Backup Lamps Trailer Wiring
PCM BPowertrain Control Module,
Fuel Pump
F/PMP Fuel Pump (Relay)
B/U LPBack-up Lamps, Automatic
Transmission Shift Lock
Control System
RR DEFOG Rear Window DefoggerFuses Usage
HDLP-HI Headlamp High Beam Relay
PRIME Not Used
02B Oxygen Sensors
SIRSupplemental Inatable
Restraint System
FRT PARKFront Parking Lamps,
Sidemarker Lamps
DRLDaytime Running
Lamps (Relay)
SEO IGN Rear Defog Relay
TBC IGN1 Truck Body Controller Ignition
HI HDLP-LT High Beam Headlamp-Left
LH HID Not Used
DRL Daytime Running Lamps
IPC/DICInstrument Panel Cluster/
Driver Information Center
HVAC/ECAS Climate Control Controller
CIG LTR Cigarette Lighter
HI HDLP-RT High Beam Headlamp-Right
HDLP-LOW Headlamp Low Beam Relay
A/C COMP Air Conditioning Compressor
5-130