2003 CHEVROLET C/K fuse

6-80
Instrument Panel Fuse Block
There are two instrument panel fuse blocks located behind the instrument panel on the passenger's side of the vehicle.
Be sure to replace fuses with fuses of the same rating. Do not use fuses of higher amperage than those indicated on
the fuse block.
Fuse Block 1

6-81
Fuse Usage
RH PARK LP Right
-hand Parking Lamps
LH PARK LP Left
-hand Parking Lamps
RADIO U Radio
PWR WINDOW Power Windows
BRAKE ISO Brake Warning Lamp
SPARE Spare Fuse
L
-RR TRUCK Left Rear Trailer Wiring
SPARE Spare Fuse
SPARE Spare Fuse
SPARE Spare Fuse
R
-RR TRUCK Right Rear Trailer Wiring
SPARE Spare FuseRelay Usage
BRAKE LAMP C4/C5 Brake Lamps, C6/C7/C8
Tractor/Trailer Wiring
IGN 4 Ignition
MARKER LP Sidemarker and Clearance Lamps
HTD FUEL LB7/LG4 Heated Fuel
AIR HTR LG4 Air Heater
ECU
MAINTAINLG4 Electronic Control Unit
DRL Daytime Running Lamps
CHMSL ISO Center High Mounted Stop Lamp
HTD MIRR Heated Mirrors
R-TRN TLR Right Trailer Turn Signal
L
-TRN TLR Left Trailer Turn Signal
SPARE Spare Relay
SPARE Spare Relay
SPARE Spare Relay

6-82
Fuse Block 2
Circuit Breaker Usage
1 Stoplamps
2 Center High Mounted Stop Lamp
3 Parking Lamps
4 Powertrain Control Module
5 Auxiliary Wiring
6 Heater/Air ConditioningCircuit Breaker Usage
7 Hazard Warning Flashers
8 Power Post
9 Courtesy Lamps
10 Warning Lights, Gages
and Indicators
11 Crank
12 Rear Axle
13 Trailer Turn Signals/Hazard
Warning Flashers
14 Radio/Chime
15 Daytime Running Lamps
16 Air Bag System
17 Exterior/Interior Lamps
18 Parking Brake
19 Accessory Power
20 Ignition
21 Sidemarker Lamps
22 Turn Signal/Backup Lamps
23 Transmission
24 Chassis
A Spare
B Spare

6-83
Underhood Fuse Block
When a circuit goes out, the problem could be in either
the primary or secondary underhood fuse blocks. These
blocks uses blade
-type fuses.
Both underhood
fuse blocks are
located in the engine
compartment, on the
passenger's side of
the vehicle.
Primary Underhood
Fuse BlockTo access the fuse blocks, gently squeeze both sides of
the cover to unlatch the tabs at the top. Then, unsnap
both attachments at the bottom and remove the cover.
Be sure to replace fuses with fuses of the same rating.
Do not use fuses of higher amperage than those
indicated on the fuse block.

6-84
Primary Underhood Fuse Block
Relay Usage
NOTE 1 LG4 Powertrain Control Valve,
L18/LB7 Fuel Pump,
LG5 Heated Fuel
IGN B Ignition
STARTER StarterRelay Usage
HORN Horn
IGN A Ignition
PTO Power Take
-Off
REVERSE Reverse
NEUTRAL
STARTNeutral Start
Fuse Usage
RR DEFOG Rear Defog
ENG 1 Engine 1
ENG 3 Engine 3
PCM
-B Powertrain Control Module
BLANK Empty
ENG 4 Engine 4
ENG 2 Engine 2
HTD FUEL Heated Fuel
BLANK Empty
BLANK Empty

6-85
Fuse Usage
BLANK Empty
A/C COMP Air Conditioning Compressor
ABS 1 Anti
-Lock Brake System 1
ABS 2 Anti
-Lock Brake System 2
ABS 3 Anti
-Lock Brake System 3
ENGINE Engine
E/A PUMP Electronic/Automatic Pump
HORN Horn
NOTE 2 L18/LB7 Fuel, LG4 Powertrain
Control Valve, LG5 Electronic
Control Module
BLANK Empty
STUD A Spare
STUD B Spare
Secondary Underhood Fuse Block
Fuse Usage
IGN 1 Ignition 1
IGN 4 Ignition 4
IGN 3 Ignition 3
BATT/HAZ Battery/Hazard Warning Flashers
HEADLAMP Headlamps
LIGHTING Interior/Exterior Lamps
HVAC Comfort Control System
NOTE C4/C5 Electric Brake,
C6/C7/C8 Brake Lamps