2004 CHEVROLET SILVERADO relay

Auxiliary Battery
The auxiliary battery provision can be used to supply
electrical power to additional equipment that you
may choose to add, such as a slide-in camper.
If your vehicle has this
provision, this relay will be
located on the passenger’s
side of the vehicle, next
to the auxiliary battery.
When using this provision, connection should only be
made to the upper stud (A) of the relay. Do not
make connections to the lower stud (B) of the relay.
The auxiliary battery circuit is protected by a megafuse
located behind the auxiliary battery.
Be sure to follow the proper installation instructions
that are included with any electrical equipment that
you install.Notice:Leaving electrical equipment on for
extended periods will drain the battery. Always turn
off electrical equipment when not in use and do
not use equipment that exceeds the maximum
amperage rating for the auxiliary battery provision.
Power Winches
If you wish to use a power winch on your vehicle, only
use it when your vehicle is stationary or anchored.
Power Take-Off (PTO)
Before using a PTO, if equipped, refer to the
manufacturer’s or installer’s instructions.
To engage a PTO on a vehicle with a manual
transmission do the following:
1. Hold the clutch pedal down.
2. Set the parking brake.
3. Shift the transmission into NEUTRAL (N).
4. Engage the PTO. Refer to the manufacturer’s
or installer’s for instructions on electrically
engaged PTOs.
5. For mobile operations, shift the transmission into
the gear you want, apply the regular brakes and
release the parking brake. For stationary operations,
leave the parking brake applied.
4-100

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

Center Instrument Panel Fuse Block
The center instrument panel utility block is located
underneath the instrument panel, to the left of the
steering column.
Device Usage
SEO Special Equipment Option
TRAILER Trailer Brake Wiring
UPFIT Uptter (Not Used)
SL RIDERide Control
Harness Connection
HDLR 2 Headliner Wiring Connector
Device Usage
BODY Body Wiring Connector
DEFOG Rear Defogger Relay
HDLNR 1 Headliner Wiring Connector 1
SPARE RELAY Not Used
CB SEATDriver and Passenger Seat
Module Circuit Breaker
CB RT DOORRight Power Windows
Circuit Breaker
SPARE Not Used
INFOInfotainment
Harness Connection
5-126

Underhood Fuse BlockThe underhood fuse block in the engine compartment
on the driver’s side of the vehicle near the battery.
Lift the cover for access to the fuse/relay block.
To remove fuses hold the end of the fuse between your
thumb and index nger and pull straight out.
SeeEngine Compartment Overview on page 5-14for
more information on its location.
5-127

*1— Gasoline Engine and Diesel Engine.
*2— Gasoline Engine; ECMRPV — Diesel Engine.
*3— Gasoline Engine; FUEL HT — Diesel Engine.
*4— Gasoline Engine; ECM I — Diesel Engine.
*5— IGN/EDU
Fuses Usage
GLOW PLUGDiesel Glow Plugs and Intake
Air Heater
CUST FEED Gasoline Accessory Power
STUD #1Auxiliary Power (Single
Battery and Diesels Only)/
Dual Battery (TP2) Do not
install fuse.
MBECMid Bussed Electrical Center
Power Feed, Front Seats,
Right Doors
BLOWER Front Climate Control Fan
LBECLeft Bussed Electrical
Center, Door Modules, Door
Locks, Auxiliary Power
Outlet — Rear Cargo Area
and Instrument Panel
Fuses Usage
STUD 2Accessory Power/Trailer
Wiring Brake Feed
ABS Anti-Lock Brakes
VSES/ECAS Vehicle Stability
IGN A Ignition Power
IGN B Ignition Power
LBEC 1Left Bussed Electrical Center,
Left Doors, Truck Body
Controller, Flasher Module
TRL PARK Parking Lamps Trailer Wiring
RR PARKRight Rear Parking and
Sidemarker Lamps
LR PARKLeft Rear Parking and
Sidemarker Lamps
PARK LP Parking Lamps Relay
STARTER Starter Relay
INTPARK Interior Lamps
STOP LP Stoplamps
TBC BATTTruck Body Controller
Battery Feed
SUNROOF Sunroof
SEO B2 Off-Road Lamps
5-129

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

Fuses Usage
A/C COMPAir Conditioning Compressor
Relay
RR WPR Not Used
RADIO Audio System
SEO B1Mid Bussed Electrical Center,
Rear Heated Seats,
HomeLink
LO HDLP-LT Headlamp Low Beam-Left
BTSIBrake Transmission Shift
Interlock System
CRANK Starting System
LO HDLP-RT Headlamp Low Beam-Right
FOG LP Fog Lamp Relay
FOG LP Fog LampsFuses Usage
HORN Horn Relay
W/S WASHWindshield Washer
Pump Relay
W/S WASH Windshield Washer Pump
INFOOnStar/Rear Seat
Entertainment
RADIO AMP Radio Amplier
RH HID Not Used
HORN Horn
EAP Not Used
TREC All-Wheel Drive Module
SBA Supplemental Brake Assist
5-131