2003 CADILLAC CTS heater

6-25
Engine Coolant
The cooling system in your vehicle is filled with
DEX
-COOL engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX
-COOL extended life coolant.
The following explains your cooling system and how
to add coolant when it is low. If you have a problem
with engine overheating, see ªEngine Overheatingº
in the Index.
A 50/50 mixture of clean, drinkable water and
DEX
-COOL coolant will:

Give freezing protection down to
-34F (-37C).

Give boiling protection up to 265F (129C).

Protect against rust and corrosion.

Help keep the proper engine temperature.

Let the warning lights and gages work as
they should.
NOTICE:
When adding coolant, it is important that you use
only DEX
-COOL (silicate-free) coolant.
If coolant other than DEX-COOL is added to the
system, premature engine, heater core or
radiator corrosion may result. In addition, the
engine coolant will require change sooner
-- at
30,000 miles (50 000 km) or 24 months,
whichever occurs first. Damage caused by the
use of coolant other than DEX
-COOL is not
covered by your new vehicle warranty.

6-26 What to Use
Use a mixture of one-half clean, drinkable water and
one
-half DEX-COOL
coolant which won't damage
aluminum parts. If you use this coolant mixture, you
don't need to add anything else.
CAUTION:
Adding only plain water to your cooling system
can be dangerous. Plain water, or some other
liquid such as alcohol, can boil before the proper
coolant mixture will. Your vehicle's coolant
warning system is set for the proper coolant
mixture. With plain water or the wrong mixture,
your engine could get too hot but you wouldn't
get the overheat warning. Your engine could
catch fire and you or others could be burned.
Use a 50/50 mixture of clean, drinkable water
and DEX
-COOL
coolant.
NOTICE:
If you use an improper coolant mixture, your
engine could overheat and be badly damaged.
The repair cost wouldn't be covered by your
warranty. Too much water in the mixture can
freeze and crack the engine, radiator, heater core
and other parts.
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
NOTICE:
If you use the proper coolant, you don't have to
add extra inhibitors or additives which claim to
improve the system. These can be harmful.

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

6-70
Minifuses Usage
INTERIOR
LAMPHush Panel Lamps, Puddle
Lamps, Overhead Courtesy
Lamp Assembly
PSGR DR MOD Right Front Passenger
Door Module
RIM RIM (Rear Integration Module),
Ignition Switch, Key Lock
Cylinder
REAR
FOG LAMPRear Fog Lamps (Export Only)
SPARE Not Used
NAV TV Tuner Assembly (Export
Only), VICS (Vehicle Information
Communication System) ModuleMinifuses Usage
SPARE Not Used
SPARE Not Used
POWER
SOUNDERPower Sounder, Inclination Sensor
SPARE Not Used
TRUNK LAMP Trunk Lamp
FUEL
PUMP MTRFuel Pump Motor
AFTERBOIL Afterboil Heater Pump
R FRT HTD
SEAT MODPassenger's Side Heated
Seat Module
SPARE Not Used
SIR SDM (Sensing Diagnostic
Module)
RIM ISRVM (Inside Rearview Mirror),
Power Sounder, RIM, Passive
Trunk Release Sensor
CANISTER
VENTCanister Vent Solenoid
SPARE Not Used

6-71
Circuit
BreakersUsage
DR MOD
PWR C/BDoor Modules
J Cases Usage
REAR DEFOG Rear Window Defogger Element
SUNROOF
MODPower Sunroof Module
Relays Usage
RAP
RELAY MINIRetained Accessory Power
SPARE Not Used
REAR DEFOG
RELAY MINIRear Window DefoggerRelays Usage
SPARE Not Used
AFTER
BOIL MICROAfterboil Heater Pump
INT LAMP
RELAY MICROHush Panel Lamps, Puddle
Lamps, Overhead Courtesy
Lamp Assembly
IGN 1 RELAY
MICROIgnition Switch
REAR FOG
LAMP RLY
MICRORear Fog Lamps (Export Only)
FUEL PUMP
MOTOR RLY
MICROFuel Pump Motor