HORN
TABLE OF CONTENTS
page page
HORN SYSTEM
DESCRIPTION..........................1
OPERATION............................1
DIAGNOSIS AND TESTING
HORN SYSTEM........................1
HORN
DIAGNOSIS AND TESTING
HORN...............................3REMOVAL.............................4
INSTALLATION..........................4
HORN SWITCH
DESCRIPTION..........................4
HORN SYSTEM
DESCRIPTION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAG, REFER TO ELECTRICAL, RESTRAINTS FOR
SAFETY PRECAUTIONS. DISCONNECT THE NEGA-
TIVE CABLE FROM THE BATTERY BEFORE SER-
VICING COMPONENTS INVOLVING THE AIRBAG
SYSTEM. ACCIDENTAL DEPLOYMENT OF AIRBAG
AND PERSONAL INJURY CAN RESULT.
The horn circuit consists of a horn switch, clock-
spring, horn relay, horns and Integrated Power Mod-
ule (IPM). The horn switch is a membrane switch
located in the airbag trim cover. The horns are
located forward of the left front wheel behind the
bumper fascia.
OPERATION
The horn relay plugs into the Integrated Power
Module (IPM) which is located in the engine com-
partment. For circuit information and component
locations, refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, details
of wire harness routing and retention, connector pin-
out information and location views for the various
wire harness connectors, splices and grounds.
The horns will not function if the switch is
ªCLOSEDº for more than 30 seconds. Once the
switch is ªOPENº, a 20±30 second delay will occur
before the horns are functional again.
DIAGNOSIS AND TESTING
HORN SYSTEM
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
Refer to Horn System Test below. If the horn does
not sound, check horn fuse located in the Integrated
Power Module (IPM). If the fuse is blown, replace
with the correct fuse. If the horns fail to sound and
the new fuse blows when depressing the horn switch,
a short circuit in the horn or the horn wiring
between the fuse terminal and the horn is responsi-
ble, or a defective horn switch allowed the horn to
burn out is responsible.
If the fuse is OK, test horn relay.
If the relay is OK, test horn.
CAUTION: Continuous sounding of horn may
cause horn failure.
Should the horn sound continuously, unplug the
horn relay from IPM.
Refer to the appropriate wiring information.
RSHORN8H-1
FIRING ORDERAUTO SHUT DOWN RELAY
DESCRIPTION
The relay is located in the Power Distribution Cen-
ter (PDC). For the location of the relay within the
PDC, refer to the PDC cover for location. Check elec-
trical terminals for corrosion and repair as necessary
OPERATION
The engine switched battery (NGC vehicles)
informs the PCM when the ASD relay energizes. A 12
volt signal at this input indicates to the PCM that
the ASD has been activated. This input is also used
to power certain drivers on NGC vehicles.
When energized, the ASD relay on NGC vehicles
provides power to operate the injectors, ignition coil,
generator field, O2 sensor heaters (both upstream
and downstream), evaporative purge solenoid, EGR
solenoid (if equipped) wastegate solenoid (if
equipped), and NVLD solenoid (if equipped).
The ASD relay also provides a sense circuit to the
PCM for diagnostic purposes. If the PCM does not
receive 12 volts from this input after grounding the
control side of the ASD relay, it sets a Diagnostic
Trouble Code (DTC). The PCM energizes the ASD
any time there is an engine speed that exceeds a pre-
determined value (typically about 50 rpm). The ASD
relay can also be energized after the engine has been
turned off to perform an O2 sensor heater test, if
vehicle is equipped with OBD II diagnostics.
As mentioned earlier, the PCM energizes the ASD
relay during an O2 sensor heater test. On NGC vehi-
cles it checks the O2 heater upon vehicle start. The
PCM still operates internally to perform several
checks, including monitoring the O2 sensor heaters.
FIRING ORDER 2.4L
Firing Order 1-2-3-4-5-6 3.3/3.8L
1 - Electrical Connector
RSIGNITION CONTROL8I-3
IGNITION CONTROL (Continued)
(4) Lower vehicle.
(5) Connect the negative cable.
SPARK PLUG
DESCRIPTION
DESCRIPTION - STANDARD 4 CYLINDER
All engines use resistor spark plugs. They have
resistance values ranging from 6,000 to 20,000 ohms
when checked with at least a 1000 volt spark plug
tester.
Do not use an ohm meter to check the resis-
tance of the spark plugs. This will give an inac-
curate reading.
Refer to the Specifications section for gap and type
of spark plug.
DESCRIPTION - PLATINUM PLUGS
The V6 engines use platinum resistor spark plugs.
They have resistance values of 6,000 to 20,000 ohms
when checked with at least a 1000 volt tester. For
spark plug identification and specifications, Refer to
the Specifications section.
Do not use an ohm meter to check the resis-
tance of the spark plugs. This will give an inac-
curate reading.When the spark plugs use a single or double plat-
inum tips and they have a recommended service life
of 100,000 miles for normal driving conditions per
schedule A in this manual. The spark plugs have a
recommended service life of 75,000 miles for severe
driving conditions per schedule B in this manual. A
thin platinum pad is welded to both or just the cen-
ter electrode end(s) as shown in (Fig. 13). Extreme
care must be used to prevent spark plug cross
threading, mis-gapping (Fig. 14) and ceramic insula-
tor damage during plug removal and installation.
CAUTION: Cleaning of the platinum plug may dam-
age the platinum tip.
Fig. 12 Knock Sensor
1 - GENERATOR
2 - INTAKE MANIFOLD
3 - KNOCK SENSOR
4-STARTER
Fig. 13 Platinum Pads
1 - APPLY ANTI-SEIZE COMPOUND HERE ONLY
2 - PLATINUM SPARK SURFACE
Fig. 14 Setting Spark Plug Electrode Gap
1 - TAPER GAUGE
RSIGNITION CONTROL8I-9
KNOCK SENSOR (Continued)
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - SELF-
DIAGNOSTICS
The instrument clusters are equipped with a self
diagnostic test feature to help identify electronic
problems. Prior to any test, perform the Self-Diag-
nostic Test. The self diagnostic system displays
instrument cluster stored fault codes in the odometer
display, sweeps the gauges to the calibration points,
and bulb checks the warning indicators. When the
key is in the ON position with the engine not run-
ning, the MIL will remain illuminated for regulatory
purposes.
To activate the Self-Diagnostic program:
(1) With the ignition switch in the OFF position,
depress the TRIP ODOMETER RESET button.
(2) Continue to hold the TRIP ODOMETER
RESET button untilSofand a number (software ver-
sion number (i.e.Sof 3.2) appears in the odometer
window then release the button. If a fault code is
present, the cluster will display it in the odometer
display. When all fault codes have been displayed,
the cluster will displayªendºin the odometer dis-
play. Refer to the INSTRUMENT CLUSTER DTC'S
table to determine what each trouble code means.
INSTRUMENT CLUSTER DTC'S
DTC DESCRIPTION
100.0 LOOP-BACK FAILURE
100.1 ABS COMMUNICATION FAULT
100.2 BCM COMMUNICATION FAULT
100.3 EATX COMMUNICATION FAULT
100.4 FCM COMMUNICATION FAULT
100.5 ORC COMMUNICATION FAULT
100.6SBEC/DEC/MCM COMMUNICATION
FAULT
200.0 AIRBAG LED SHORT
200.1 AIRBAG LED OPEN
200.2 ABS LED SHORT
200.3 ABS LED OPEN
200.6 EL INVERTER TIME-OUT
200.7 EATX MISMATCH
400.0 EEPROM READ/WRITE FAILURE
400.1IMPROPER POWER DOWN
DETECTED
CALIBRATION TEST
The CLUSTER CALIBRATION table contains the
proper calibration points for each gauge. If the gauge
pointers are not calibrated, a problem exists in the
cluster. If any gauge is out of calibration, replace the
cluster.
CLUSTER CALIBRATION
SPEEDOMETER CALIBRATION POINT
1 0 MPH (0 KM/H)
2 20 MPH (40 KM/H)
3 60 MPH (100 KM/H)
4 100 MPH (160 KM/H)
TACHOMETER
1 0 RPM
2 1000 RPM
3 3000 RPM
4 6000 RPM
FUEL GAUGE
1 EMPTY
2 1/4 FILLED
3 1/2 FILLED
4 FULL
TEMPERATURE
GAUGE
1 COLD
2 1/4
3 3/4
4 HOT
ODOMETER SEGMENT TEST
If a segment in the odometer does not illuminate
normally, a problem exists in the display.
ELECTRONIC TRANSMISSION RANGE INDICATOR
SEGMENT TEST
If a segment in the transmission range indicator
does not illuminate normally, a problem exists in the
display.
8J - 2 INSTRUMENT CLUSTERRS
INSTRUMENT CLUSTER (Continued)
(3) Install the retaining screws.
(4) Reconnect the battery negative cable.
FRONT FOG LAMP
DIAGNOSIS AND TESTING - FRONT FOG LAMP
When a vehicle experiences problems with the
front fog lamp system, verify the condition of the bat-
tery connections, fuses, charging system, fog lamp
bulbs, wire connectors, relay, high beam switch, and
headlamp switch. Refer to the appropriate wiring
information.
Each vehicle is equipped with various lamp assem-
blies. A good ground is necessary for proper lighting
operation. Grounding is provided by the lamp socket
when it comes in contact with the metal body, or
through a separate ground wire.
When changing lamp bulbs check the socket for
corrosion. If corrosion is present, clean it with a wire
brush.
When it is necessary to remove components to ser-
vice another, it should not be necessary to apply
excessive force or bend a component to remove it.
Before damaging a trim component, verify hidden
fasteners or captured edges are not holding the com-
ponent in place.
FRONT FOG LAMP DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF.1. Loose or corroded battery
cables.1. Clean and secure battery cable clamps and
posts.
2. Loose or worn generator drive
belt.2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system. Refer to
Electrical, Charging,
4. Battery has insufficient charge. 4. Test battery state-of-charge. Refer to
Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery. Refer to Electrical, Battery
System.
6. Poor lighting circuit Z349/Z248
ground.6. Test for voltage drop across Z349/248
ground locations. Refer to Electrical, Wiring
Information.
FOG LAMP BULBS
BURN OUT
FREQUENTLY1. Charging system output too
high.1. Test and repair charging system. Refer to
Electrical, Charging.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
Fig. 7 CHMSL ELECTRICAL CONNECTOR
1 - CHMSL UNIT
2 - CHMSL ELECTRICAL CONNECTOR
RSLAMPS/LIGHTING - EXTERIOR8L-7
CENTER HIGH MOUNTED STOP LAMP UNIT (Continued)
HEADLAMP
DIAGNOSIS AND TESTING - HEADLAMP
When a vehicle experiences problems with the
headlamp system, verify the condition of the battery
connections, fuses, charging system, headlamp bulbs,
wire connectors, relay, high beam switch, dimmer
switch, and headlamp switch. Refer to the appropri-
ate wiring information.
Each vehicle is equipped with various lamp assem-
blies. A good ground is necessary for proper lighting
operation. Grounding is provided by the lamp socketwhen it comes in contact with the metal body, or
through a separate ground wire.
When changing lamp bulbs check the socket for
corrosion. If corrosion is present, clean it with a wire
brush.
When it is necessary to remove components to ser-
vice another, it should not be necessary to apply
excessive force or bend a component to remove it.
Before damaging a trim component, verify hidden
fasteners or captured edges are not holding the com-
ponent in place.
HEADLAMP DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF.1. Loose or corroded battery
cables.1. Clean and secure battery cable clamps and
posts.
2. Loose or worn generator drive
belt.2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system, refer to
Electrical, Charging
4. Battery has insufficient charge. 4. Test battery state-of-charge, refer to
Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery, refer to Electrical, Battery
System.
6. Poor lighting circuit Z343/Z344-
ground.6. Test for voltage drop across Z343/Z344-
ground locations, refer to Electrical, Wiring
Diagram Information.
HEADLAMP BULBS
BURN OUT
FREQUENTLY.1. Integrated Power Module (IPM)
not controlling voltage.1. Test and repair Integrated Power Module.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
HEADLAMPS ARE DIM
WITH ENGINE
RUNNING ABOVE IDLE.1. Charging system output too low. 1. Test and repair charging system, refer to
Electrical, Wiring Information.
2. Poor lighting circuit Z343/Z344-
ground.2. Test for voltage drop across Z343/Z344-
ground locations, refer to Electrical, Wiring
Information.
3. High resistance in headlamp
circuit.3. Test amperage draw of headlamp circuit.
RSLAMPS/LIGHTING - EXTERIOR8L-11
WARNING: IF REMOVAL OF AIRBAG MODULE IS
NECESSARY, REFER TO THE RESTRAINT SYS-
TEMS SECTION FOR MORE INFORMATION.
(1) Remove the negative battery cable.
(2) Turn off ignition.
(3) Remove the air bag, refer to the restraint sec-
tion for more information.
(4) Remove the screw from bottom of the switch.
(5) Remove switch from steering wheel.
(6) Disconnect two-way electrical connector.
(7) Repeat for the other switch.
INSTALLATION
The speed control switches are mounted in the
steering wheel and wired through the clock spring
device under the airbag module.
WARNING: IF REMOVAL OF AIRBAG MODULE IS
NECESSARY, REFER TO THE RESTRAINT SYS-
TEMS SECTION FOR MORE INFORMATION.
(1) Connect two-way electrical connector.
(2) Install switch.
(3) Install screw for the switch.
(4) Repeat for the other switch.
(5) Install the air bag, refer to the restraint section
for more information.
(6) Install the negative battery cable.
VACUUM RESERVOIR
DESCRIPTION
The vacuum reservoir is located in the engine com-
partment. It is made of plastic.
OPERATION
The reservoir stores engine vacuum. Manifold vac-
uum is supplied from the brake booster check valve.
The speed control vacuum supply hose has a check
valve at the source (brake booster) to maintain the
highest available vacuum level in the servo, reservoir
and vacuum hoses. When engine vacuum drops, as in
climbing a grade while driving, the reservoir supplies
the vacuum needed to maintain proper speed control
operation. The vacuum reservoir cannot be repaired
and must be replaced if faulty.
REMOVAL
(1) Release hood latch and open hood.
(2) Disconnect the negative battery cable.
(3) Disconnect the vacuum line to the battery tray/
vacuum reservoir.
(4) Remove battery tray/vacuum reservoir, refer to
the Battery section for more information.
INSTALLATION
(1) Install battery tray/vacuum reservoir, refer to
the Battery section for more information.
(2) Connect vacuum line that leads to the battery
tray/vacuum reservoir.
(3) Connect the negative battery cable.
8P - 6 SPEED CONTROLRS
SWITCH (Continued)
OPERATION
FRONT WIPER/WASHER SYSTEM
The windshield washer circuit is protected by a 15
amp Cartridge Fuse located in the IPM. The wiper
motor has permanent magnetic fields. The speeds are
determined by current flow to the appropriate set of
brushes inside the motor. The current flow is con-
trolled by the multi-function switch. The high speed/
low speed relays are located in the IPM. The speed
sensitive intermittent wiper is controlled by the Body
Control Module (BCM). The intermittent mode, with
the vehicle traveling greater than 10.4 mph, has a
range of 0.5 to 18 seconds. With the vehicle traveling
less than 10.4 mph, the time delay doubles to a
range of 1 to 36 seconds. The wiper arms will park at
the base of the windshield just above the cowl cover
after the wiper switch is turned OFF.
The windshield wiper motor and linkage is located
in an integral wiper unit at the rear of the engine
compartment. The wiper unit must be removed to
gain access to the wiper motor.
The front and rear washer systems share the same
washer pump motor.
REAR WIPER/WASHER SYSTEM
When rear wiper operation is required, the BCM
will provide ignition ON voltage to the rear wiper
motor (Export and ATC equipped vehicles only).
When the wiper switch is turned OFF, the BCM pro-
vides circuit ground to operate the motor until the
wipe cycle is complete and the wiper arm returns to
the base of the rear window.
Switch only offers an intermittent rear wiper
mode. The wiper motor will cycle every 7 seconds.
The intermittent delay time is also adjusted based
upon vehicle speed. With the vehicle traveling
greater than 50 mph, the cycle changes to every 5
seconds.
When rear washer is requested by depressing and
holding down the switch, the BCM then provides a
ground for the washer motor. Until the switch is
released, the motor will be in a continuous wipe
mode, then return to an intermittent wipe mode.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - FRONT WIPER
SYSTEM
The windshield wiper system operates in several
modes:
²Low and high speed normal wipe
²Speed sensitive intermittent wipe
²Wipe after wash
²Park (switch OFF)The windshield wiper circuits are continuously
monitored and controlled by the Body Control Mod-
ule (BCM). If a problem occurs in the electronic com-
ponents, wiring, switch (except integral motor park
switch) and wiper motor a Diagnostic Trouble Code
(DTC) will be stored in the BCM memory. DTC's can
be retrieved using a DRB IIItscan tool. Refer to the
proper Body Diagnostic Procedures manual for DTC
descriptions and retrieval information.
The windshield wiper park switch and circuit is
monitored by the BCM. The park switch and circuit
can be tested using the Wiper System Diagnosis
table.
DIAGNOSIS AND TESTING - FRONT
WIPER/WASHER SWITCH
(1) Remove the multi-function switch (Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
MULTI-FUNCTION SWITCH - REMOVAL).
(2) Using an ohmmeter check resistance readings
between switch pins. Refer to the WIPER/WASHER
SWITCH RESISTANCE table.
WIPER/WASHER SWITCH RESISTANCE
SWITCH POSITION RESISTANCE BETWEEN
OFF 1 AND 2 = 23.9KV 5%
DELAY POSITION
1ST 1 AND 2 = 7.9KV 5%
2ND 1 AND 2 = 4.6KV 5%
3RD 1 AND 2 = 2.9KV 5%
4TH 1 AND 2 = 1.9KV 5%
5TH 1 AND 2 = 1.3KV 5%
LOW 1 AND 2 = 670V 5%
HIGH 1 AND2=240V 5%
WASH 1 AND 4 = 5.9KV 5%
DIAGNOSIS AND TESTING - FAILED PARK
SWITCH
If the wiper park switch has failed, the windshield
wipers will operate as follows:
²SWITCH OFF- Wipers stop in current location
regardless of the park signal.
²INTERMITTENT MODE- Wipers operate con-
tinuously or at low speed for one or more extra
wipes.
²LOW SPEED- Wipers operate at low speed.
²HIGH SPEED- Wipers operate at high speed.
8R - 2 WIPERS/WASHERSRS
WIPERS/WASHERS (Continued)