2003 CADILLAC CTS Owners Manual

6-59
Electrical System
Add-On Electrical Equipment
NOTICE:
Don't add anything electrical to your vehicle
unless you check with your dealer first. Some
electrical equipment can damage your vehicle
and the damage wouldn't be covered by your
warranty. Some add
-on electrical equipment
can keep other components from working as
they should.
Your vehicle has an air bag system. Before attempting to
add anything electrical to your vehicle, see ªServicing
Your Air Bag
-Equipped Vehicleº in the Index.
Windshield Wiper Fuses
The windshield wiper motor is protected by an internal
circuit breaker. If the wiper motor overheats due to
heavy snow, the wipers will stop until the motor cools
and will then restart.
Power Windows and Other Power Options
Circuit breakers protect the power windows and power
seats. When the current load is too heavy, the circuit
breaker opens and closes, protecting the circuit until the
problem is fixed or goes away.

6-60 Fuses and Circuit Breakers
The wiring circuits in your vehicle are protected from
short circuits by a combination of fuses and circuit
breakers. This greatly reduces the chance of fires caused
by electrical problems.
Look at the silver
-colored band inside the fuse. If the
band is broken or melted, replace the fuse. Be sure you
replace a bad fuse with a new one of the identical size
and rating. If a fuse blows, see your dealer for service
immediately.
If you ever have a problem on the road and don't have a
spare fuse, you can ªborrowº one that has the same
amperage. Pick some feature of your vehicle that you
can get along without
-- like the radio or cigarette
lighter
-- and use its fuse, if it is the correct amperage.
Replace it as soon as you can.
The fuses are located in three fuse blocks, one located in
the engine compartment on the passenger's side and the
other two under the rear seat.Underhood Fuse BlockThe underhood fuse block is located in the engine
compartment on the passenger's side of the vehicle. See
ªEngine Compartment Overviewº in the Index for more
information on location.
To access the fuses, push in the two tabs located on each
side of the fuse block cover. Then lift the cover off.

6-61
Relays Usage
LO SPEED FAN
RELAY MINILow Speed Fan Motor
HI SPEED FAN
RELAY MINIHigh Speed Fan MotorRelays Usage
ACCESSORY
RELAY MINIAccessory Power Outlets
S/P FAN
RELAY MINISeries/Parallel Fan
PARK LAMP
RELAY MICROParking Lamps
HORN RELAY
MICROHorn
HI BEAM
RELAY MICROHigh
-Beam Headlamps
DRL RELAY
MICRO
- OPTDaytime Running Lamps
LO BEAM
RELAY/HID
MINI
- OPTLow
-Beam HID Headlamps
(Option)
HDLP WASH
RELAY
MINI
- OPTHeadlamp Washer Motor (Option)
CIGAR
RELAY MINICigarette Lighter (Option)

6-62
Relays Usage
BLOWER
RELAY MINIFront Blower
FOG LAMP
RELAY MICROFog Lamps
MAIN RELAY
MICROPowertrain/ECM
STARTER
RELAY MINIStarter Solenoid
CMP CLU
RELAY MICROCompressor Clutch
IGN
-1 RELAY
MICROIgnition Switch (ON)
Wiring
HarnessesUsage
BODY W/H Wiring Harness Connection
BODY W/H Wiring Harness Connection
ENG W/H Engine Wiring Harness
ConnectionJ Cases Usage
R REAR RRPDB (Passenger's Side Rear
Power Distribution Box)
R REAR RRPDB (Passenger's Side Rear
Power Distribution Box)
L REAR LRPDB (Driver's Side Rear
Power Distribution Box)
L REAR LRPDB (Driver's Side Rear
Power Distribution Box)
HI FAN High Cooling Fan Motor
LO FAN Low Cooling Fan Motor
BLOWER PWM Fan Motor Assembly
STARTER Starter Solenoid
EBCM Electronic Brake Control Module
Mini Fuses Usage
RT PARK Passenger's Side Taillamp
Assembly, Front Sidemarker and
Front Parking Lamp Assembly
HORN Dual Horn Assembly

6-63
Mini Fuses Usage
LT HI BEAM Driver's Side High
-Beam
Headlamp
LT LOW BEAM Driver's Side Low
-Beam
Headlamp
RT LOW BEAM Passenger's Side Low
-Beam
Headlamp
RT HI BEAM Passenger's Side High
-Beam
Headlamp
SPARE Not Used
SPARE Not Used
THEFT ECM (Electronic Control
Module), TCM (Transmission
Control Module), PASS
-Key III+
Module
LT PARK Driver's Side Taillamp Assembly,
Front Sidemarker and Front
Parking Lamp Assembly
LIC/DIMMING Rear License Plate
Assembly, DIMMini Fuses Usage
DIM/ALDL DIM, ALDL (Assembly Line
Data Link)
FLASHER Turn Signal/Hazard Flasher
Module
MANIFOLD Manifold Flaps 1 and 2, Air Mass
Meter, Canister Purge Valve
STRG CTLS Steering Wheel Control Pad,
Headlamp Switch
HTR
VLV/CLTCHHeater Valve, Clutch Switch
(Normal Closed), Clutch Switch
(Normal Open), Jumper to Start
Relay Coil for Automatic
Transmission
WASH NOZ Driver's and Passenger's Side
Heated Washer Nozzles
ECM Electronic Control Module
TCM/IPC TCM, ECM and IPC
(Instrument Panel Cluster)
SPARE Not Used
IGN MOD Front Bank Ignition Modules

6-64
Mini Fuses Usage
ELEC PRNDL Electronic PRNDL
TCC/ET TCC/ET Brake Switch (Extended
Travel), TCC/ET Brake Switch
(Cruise Disable)
STOP LP SW Stop Lamp Switch
IGN SW Ignition Switch (Power to IGN
-3
and CRANK)
VOLT CHECK DIM (Dash Integration Module)
ECM/TCM TCM (Transmission Control
Module), ECM (Electronic
Control Module), IPC (Instrument
Panel Cluster), PASS
-Key III+
Module
WPR MOD Windshield Wiper Module
Assembly
INJ Fuel Injectors
COMP
CLUTCHCompressor Clutch
WPR SW Windshield Wiper/Washer SwitchMini Fuses Usage
FOG LAMP Fog Lamps
OUTLET Center Console Accessory
Power Outlet
POST 02 Driver's and Passenger's Side
Oxygen Sensors, LRPDB
(Pusher Cooling Fan Relay)
I/P OUTLET Instrument Panel Accessory
Power Outlet
CCP Climate Control Panel
PRE 02 Driver's and Passenger's Side
Oxygen Sensors, Transmission
Output Speed Sensor
SPARE Not Used
SPARE Not Used
SPARE Not Used
Circuit
BreakersUsage
HDLP WASH
C/B
- OPTHeadlamp Washer Motor (Option)

6-65
Removing the Rear Seat Cushion
NOTICE:
A fuse center is located under the rear seat
cushion. To help avoid damage to the fuse
center, be careful when removing or reinstalling
the seat cushion.
To remove the rear seat cushion, do the following:
1. Pull up on the front of the cushion to release the
front hooks.
2. Pull the cushion up and out toward the front of
the vehicle.
3. Slide the cushion out one of the rear doors and set
it aside.
Rear Pass-Through Seat

6-66
Split-Folding Rear Seat
CAUTION:
A safety belt that isn't properly routed through
the seat cushion or is twisted won't provide the
protection needed in a crash. If the safety belt
hasn't been routed through the seat cushion at
all, it won't be there to work for the next
passenger. The person sitting in that position
could be badly injured. After reinstalling the seat
cushion, always check to be sure that the safety
belts are properly routed and are not twisted.