Fuses 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
LOCKSRear Doors and Liftgate
Power Lock Relay Feed
ECC Liftgate
TBC 2C Truck Body Controller
FLASH Flasher Module
CB LT DOORSLeft Rear Power Window
Circuit Breaker and Driver
Door Module
TBC 2B Truck Body Controller
TBC 2A Truck Body Controller
Circuit Breaker Usage
AUX PWR 2 Midgate Controller (SUT Only)
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
TRAILERTrailer Brake Wiring,
Off-Road Lamps Harness
Connector
UPFIT Up tter (Not Used)
SL RIDE Ride Control (Not Used)
HDLR 2Headliner Wiring
Connector 2
506
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 DOORRear Right Power Window,
Passenger Door Module
SPARE Not Used
INFO Not UsedUnderhood Fuse Block
The underhood fuse block in the engine
compartment is located on the driver’s side of
the vehicle near the battery. Lift the cover for
access to the fuse/relay block.
To remove fuses if you don’t have a fuse extractor,
hold the end of the fuse between your thumb
and index nger and pull straight out.
SeeEngine Compartment Overview on page 402
for more information on its location.
507
*1— Gasoline Engine and Fuel Injection Rail #2.
*2— Gasoline Engine and Fuel Injection Rail
#1.
*3— Gasoline Engine; Oxygen Sensors.
*4— Gasoline Engine; Oxygen Sensors.
*5— Ignition 1
*6— Powertrain Control Module, Fuel Pump.
*7— Supplemental Brake Assist.
*8— Sunroof.
Fuses Usage
GLOW PLUG Not Used
CUST FEED Gasoline Accessory Power
HYBRID Not Used
WSW/HTRHeated Windshield Washer
(Special Edition Only)
STUD #1Accessory Power/Trailer
Wiring
MBEC 1Mid Bussed Electrical Center
Power Feed, Front Seats,
Right Doors
Fuses Usage
BLWR Front Climate Control Fan
LBEC 2Left Bussed Electrical Center,
Door Modules, Door Locks,
Auxiliary Power Outlet—Rear
Cargo Area and Instrument
Panel
STUD #2*Accessory Power/Trailer
Wiring Brake Feed
ABS Anti-lock Brakes
VSES/ECASElectronically Controlled Air
Suspension
IGN A Ignition Switch
IGN B Ignition Switch
LBEC 1Left Bussed Electrical Center,
Left Doors, Truck Body
Controller, Flasher Module
TRL PARK Parking Lamps Trailer Wiring
RR PARKPassenger’s Side Rear
Parking and Sidemarker
Lamps
LR PARKDriver’s Side Rear Parking
and Sidemarker Lamps
509
Fuses Usage
PARK LP Parking Lamps Relay
STRTR Starter Relay
INTPARK Roof Marker Lamps
STOP LP Stoplamps
TBC BATTTruck Body Controller
Battery Feed
SEO B2 Off-Road Lamps
4WS Not Used
AUX PWRInstrument Panel Outlets,
Rear Cargo Area Power
Outlets, Console
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, Electronic Brake
Controller TC2 Mode Switch
RTDElectronic Brake Controller
Battery FeedFuses Usage
TRL B/U Backup Lamps Trailer Wiring
F/PMP Fuel Pump (Relay)
B/U LPBack-up Lamps, Automatic
Transmission Shift Lock
Control System
RR DEFOG Rear Window Defogger
HDLP-HI Headlamp High Beam Relay
PRIME Not Used
AIRBAGSupplemental In atable
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-LTDriver’s Side High Beam
Headlamp
LH HID Not Used
DRL Daytime Running Lamps
510
Fuses Usage
RVC Regulated Voltage Control
IPC/DICInstrument Panel Cluster/
Driver Information Center
HVAC/ECASClimate Control
Controller/Electronically
Controlled Air Suspension
CIG LTR Cigarette Lighter
HI HDLP-RTPassenger’s Side High Beam
Headlamp
HDLP-LOW Headlamp Low Beam Relay
A/C COMPAir Conditioning
Compressor Relay
A/C COMP Air Conditioning Compressor
TCMB Transmission Control Module
RR WPR Rear Wiper/Washer
RADIO Audio System
SEO B1Mid Bussed Electrical Center,
Universal Home Remote
System, Rear Heated Seats
LO HDLP-LTDriver’s Side Headlamp
Low BeamFuses Usage
BTSIBrake Transmission Shift
Interlock System
CRNK Starting System
LO HDLP-RTPassenger’s Side Headlamp
Low Beam
FOG LP Not Used
FOG LP Not Used
HORN Horn Relay
W/S WASHWindshield and Rear Window
Washer Pump Relay
W/S WASHWindshield and Rear Window
Washer Pump
INFO OnStar
®
RADIO AMP Radio Ampli er
RH HID Not Used
HORN Horn
EAP Not Used
TREC Four-Wheel Drive Module
SBA Not Used
511
(d)Visually inspect wiper blades for wear or
cracking. Replace wiper blades that appear worn
or damaged or that streak or miss areas of
the windshield.
(e)Make sure the safety belt reminder light and all
your belts, buckles, latch plates, retractors, and
anchorages are working properly. Look for any
other loose or damaged safety belt system parts.
If you see anything that might keep a safety belt
system from doing its job, have it repaired. Have
any torn or frayed safety belts replaced. Also look
for any opened or broken airbag coverings, and
have them repaired or replaced. The airbag system
does not need regular maintenance.
(f)Lubricate all key lock cylinders, hood latch
assembly, secondary latch, pivots, spring anchor,
release pawl, rear compartment hinges, outer
liftgate handle pivot points, rear door detent link,
roller mechanism, liftgate handle pivot points, latch
bolt, fuel door hinge, cargo door hinge, locks,
and folding seat hardware. More frequent
lubrication may be required when exposed to a
corrosive environment. Applying silicone grease on
weatherstrips with a clean cloth will make them
last longer, seal better, and not stick or squeak.Spare tire carrier hinge and latch: Inspect for leaks
and lubricate if required. Remove the setscrew
at the hinge casting and add lubricant, moving the
hinge back and forth periodically, until lubricant
can be seen coming from the setscrew opening.
Install setscrew and tighten to 7 ft lb (9
Y).
SeeRecommended Fluids and Lubricants
on page 528for what lubricant to use.
(g)Check vent hose at transfer case for kinks and
proper installation.
(h)Change automatic transmission uid and lter
if the vehicle is mainly driven under one or
more of these conditions:
In heavy city traffic where the outside
temperature regularly reaches 90°F (32°C)
or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police, or
delivery service.
522
Automatic Transmission Shift Lock
Control System Check
{CAUTION:
When you are doing this inspection, the
vehicle could move suddenly. If the vehicle
moves, you or others could be injured.
1. Before you start, be sure you have enough
room around the vehicle. It should be parked
on a level surface.
2. Firmly apply the parking brake. SeeParking
Brake on page 133.
Be ready to apply the regular brake
immediately if the vehicle begins to move.
3. With the engine off, turn the ignition to RUN,
but do not start the engine. Without applying
the regular brake, try to move the shift
lever out of PARK (P) with normal effort. If the
shift lever moves out of PARK (P), contact
your GM Goodwrench
®dealer for service.
Ignition Transmission Lock Check
While parked, and with the parking brake set, try
to turn the ignition to LOCK in each shift lever
position.
The ignition should turn to LOCK only when
the shift lever is in PARK (P).
The ignition key should come out only
in LOCK.
Contact your GM Goodwrench
®dealer if service is
required.
526