(1) Check the fuse(s) in the junction block and the
Power Distribution Center (PDC). If OK, go to Step
2. If not OK, repair the shorted circuit or component
as required and replace the faulty fuse(s).
(2) Check for battery voltage at the fuse in the
PDC. If OK, go to Step 3. If not OK, repair the open
circuit to the battery as required.
(3) Turn the ignition switch to the ON position.
Check for battery voltage at the fuse in the junction
block. If OK, go to Step 4. If not OK, repair the open
circuit to the ignition switch as required.
(4) Turn the ignition switch to the OFF position.
Disconnect and isolate the battery negative cable.
Remove the instrument cluster center bezel. Remove
the radio, but do not unplug the wire harness connec-
tors. Check for continuity between the radio chassis
and a good ground. There should be continuity. If
OK, go to Step 5. If not OK, repair the open radio
chassis ground circuit as required.
(5) Connect the battery negative cable. Turn the
ignition switch to the ON position. Check for battery
voltage at the fused ignition switch output circuit
cavity of the left (gray) radio wire harness connector.
If OK, go to Step 6. If not OK, repair the open circuit
as required.
(6) Turn the ignition switch to the OFF position.
Check for battery voltage at the fused B(+) circuit
cavity of the left (gray) radio wire harness connector.
If OK, replace the faulty radio. If not OK, repair the
open circuit to the Ignition-Off Draw (IOD) fuse as
required.
REMOTE RADIO SWITCHES
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable. Wait two minutes for the airbag system capac-
itor to discharge before further service.
(2) Remove the remote radio switch(es) from the
steering wheel.
(3) Use an ohmmeter to check the switch resis-
tance as shown in the Remote Radio Switch Test
table (Fig. 8).
NOTE: The right remote radio switch back is white
in color. The left switch back is black in color. The
right/left remote radio switch orientation is with the
steering wheel installed, and driver in drivers seat.(4) If the switch resistance checks OK, go to Step
5. If not OK, replace the faulty switch.
(5) Check for continuity between the ground cir-
cuit cavity of the switch wire harness connector and
a good ground. There should be continuity. If OK, go
to Step 6. If not OK, repair the open circuit as
required.
(6) Unplug the 24-way white wire harness connec-
tor from the Body Control Module (BCM). Check for
continuity between the radio control circuit cavity of
the remote radio switch wire harness connector and a
good ground. There should be no continuity. If OK, go
to Step 7. If not OK, repair the short circuit as
required.
(7) Check for continuity between the radio control
circuit cavities of the remote radio switch wire har-
ness connector and the BCM wire harness connector.
There should be continuity. If OK, refer to the proper
Diagnostic Procedures manual to test the BCM and
the CCD data bus. If not OK, repair the open circuit
as required.
Fig. 8 Remote Radio Switches
REMOTE RADIO SWITCH TEST
SWITCH POSITION RESISTANCE
VOLUME UP 7320 OHMS
VOLUME DOWN 1210 OHMS
SEEK UP 4530 OHMS
SEEK DOWN 2050 OHMS
PRE-SET STATION ADVANCE 10 OHMS
8F - 6 AUDIO SYSTEMSNS
DIAGNOSIS AND TESTING (Continued)
FRONT DOOR SPEAKER
REMOVAL
(1) Remove front door trim panel as necessary to
gain access to door speaker. Refer to Group 23, Body
for proper procedures.
(2) Remove screws holding speaker to bracket (Fig.
16).
(3) Remove speaker from bracket.
(4) Disconnect wire connector from speaker.
(5) Remove speaker.
INSTALLATION
For installation, reverse the above procedure.
REMOTE RADIO SWITCHES
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO GROUP 8M - PASSIVE
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
REMOVAL
(1) Disconnect and isolate the battery negative
cable. Wait two minutes for the airbag system capac-
itor to discharge before further service.
(2) From the underside of the steering wheel,
remove the (3) bolts that secure the driver side air-
bag module to the steering wheel.
(3) Pull the airbag module away from the steering
wheel far enough to access the wire harness connec-
tors on the back of the airbag module.
(4) Unplug the airbag module and horn switch
wire harness connectors from the back of the airbag
module.
(5) Remove the driver side airbag module from the
vehicle.
(6) Remove the steering wheel from the steering
column. Refer to Group 19±Steering, for service pro-
cedure.
(7) Unplug the wire harness connector from the
remote radio switch (s).
(8) Remove three screws securing steering wheel
rear cover. Refer to Group 19, Steering for serivce
procedure.
(9) Remove the remote radio switch from the steer-
ing wheel by depressing tabs on each side of switch..
NOTE: The right remote radio switch back is white
in color. The left switch back is black in color. The
right/left remote radio switch orientation is with the
steering wheel installed, and driver in drivers seat.
INSTALLATION
For installation, reverse the above procedure. The
switches can only be installed one way. Be careful to
index them correctly before pressing them into place.
Tighten the airbag module mounting screws to 10.2
N´m (90 in. lbs.).
Fig. 15 Right Instrument Panel Speaker
Fig. 16 Front Door Speaker
NSAUDIO SYSTEMS 8F - 9
REMOVAL AND INSTALLATION (Continued)
(b) If the horn does not sound, install horn relay
and refer to Horn Test.
HORNS WILL NOT SOUND
Check horn fuse 6 in the Power Distribution Cen-
ter and fuse 7 in the Junction Block. If fuse is blown
refer to FUSE BLOWN section. If fuse is OK, refer to
FUSE OK section.
FUSE BLOWN
(1) Verify condition of battery terminals and volt-
age, refer to Group 8A, Battery. If battery connec-
tions and battery charge is OK proceed to Step 2.
(2) Using a voltmeter, test for battery voltage at
both sides of horn fuse 7. If voltage is OK, on both
sides of fuse, proceed to Fuse OK. If voltage is OK,
on one side of fuse, the fuse is blown, proceed to Step
3.
(3) Using a suitable ammeter in place of the fuse,
test amperage draw of the horn circuit. If amperage
draw is greater than 20 amps without the horn
switch depressed, a grounded circuit exists between
the fuse and the horn relay. Proceed to Step 4. If
amperage draw is greater than 20 amps with the
horn switch depressed, a grounded circuit exists
between the horn relay and the horn. Proceed to step
Step 5.
(4) Remove the horn relay from the Junction
Block. If the amperage draw drops to 0 amps, the
horn switch or circuit is shorted. Refer to group 8W,
Wiring Diagrams for circuit information. If the
amperage draw does not drop to 0 amps, repair short
at the Junction Block.
(5) Disengage a wire connector from one of the
horns. If amperage drops and the connected horn
sounds, replace the faulty horn. If amperage does not
drop with both horns disconnected and the horn
switch depressed, proceed to Step 6.
(6) Using a continuity tester, with the horns dis-
connected test continuity of the X2 cavity of the horn
relay to ground. Refer to Group 8W, Wiring Diagrams
for circuit information. If continuity is detected, the
circuit is grounded between the Junction Block and
the horns. Locate and repair pinched harness.
FUSE OK
(1) Remove the horn relay from the Junction
Block.
(2) Using a continuity tester, Depress horn switch
and test continuity from the X3 cavity of the horn
relay to ground. Refer to Group 8W, Wiring Diagrams
for circuit information.
(a) If continuity is detected, proceed to Step 3.
(b) If NO continuity, proceed to Step 4.
(3) Using a suitable jumper wire, jump across the
fuse F62 cavity and the X2 cavity of the horn relay in
the Junction Block.
(a) If the horn sounds, replace the horn relay.
(b) If the horn does not sound, proceed to Step 4.
(4) Remove airbag/horn pad from steering wheel.
Refer to Group 8M, Restraint Systems for proper pro-
cedures.
(5) Test continuity across horn switch connectors
with horn switch depressed.
(a) If continuity is detected, repair open circuit
between the relay and the horn switch.
(b) If NO continuity, replace airbag cover.
(6) Install horn relay into Junction Block.
(7) Disengage wire connectors from horns.
(8) Using a voltmeter, with the horn switch
depressed test voltage across horn connector termi-
nals of the wire harness (Fig. 3).
(a) If voltage is detected, replace horns.
(b) If NO voltage, proceed to step Step 9.
(9) With the horn switch depressed, test for volt-
age between the X2 circuit and ground.
(a) If voltage OK, repair system ground at right
cowl area. Refer to Group 8W, Wiring Diagrams.
(b) If NO voltage, repair open X2 circuit between
the relay and the horns.
Fig. 2 Horn Relay
Fig. 3 Horn and Connector
8G - 2 HORNSNS
DIAGNOSIS AND TESTING (Continued)
HORNS SOUND CONTINUOUSLY
CAUTION: Continuous sounding of horns may
cause relay to fail.
The horn switch (membrane) sometimes can be the
cause without the switch being depressing.
(1) Remove the horn relay from the junction block.
(2) Using a continuity tester, test continuity from
the X3 cavity of the horn relay to ground. Refer to
Group 8W, Wiring Diagrams for circuit information.
(a) If continuity is detected, proceed to step Step
3.
(b) If NO continuity, replace the horn relay.
(3) Remove the airbag/horn pad from the steering
wheel and disengage horn connector.
(4) Install horn relay into junction block.
(a) If horn does not sound, replace airbag cover/
horn pad.
(b) If horn sounds, repair grounded X3 circuit
from junction block to clockspring in steering in
steering column. Refer to Group 8W, Wiring Dia-
grams.
HORN SYSTEM
Refer to Horn System Test below. If the horn does
not sound, check horn fuse located in the Power Dis-
tribution Center. If the fuse is blown, replace with
the correct fuse. If the horn 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 responsible, or a
defective horn switch allowed the horn to burn out is
responsible.
If the fuse is OK, test horn relay refer to Horn
Relay Test.
If the relay is OK, test horn. Refer to Horn System
Test.
CAUTION: Continuous sounding of horn may
cause horn relay to fail.
Should the horn sound continuously:
²Unplug the horn relay from Power Distribution
Center.
²Refer to Horn Relay Test.
Refer to Group 8W, Wiring Diagrams for circuit
and wiring information.
HORN SYSTEM TEST
CONDITION POSSIBLE CAUSE CORRECTION
Horn sounds continuously.
NOTE: Immediately unplug horn
relay in the Power Distribution
Center (PDC)(1) Faulty horn relay.
(2) Horn control circuit to relay
shorted to ground.
(3) Pinched horn switch wire under
Driver Airbag Module.
(4) Defective horn switch(1) Refer to horn relay test.
(2) Check terminal 85 in Junction
Block for continuity to ground. If
continuity to ground indicates:
(a) Steering Wheel horn switch/lead
shorted to ground.
(b) Wiring harness shorted to
ground. Find the short and repair as
necessary.
(3) Replace Driver Airbag Module.
(4) Replace Driver Airbag Module.
Horn sound intermittently as the
steering wheel is turned.(1) Horn relay control circuit X3 is
shorted to ground inside steering
column or wheel.
(2) Pinched horn switch wire under
Driver Airbag Module
(3) Defective horn switch(1) Remove Driver Airbag Module
and/or wheel. Check for rubbing or
loose wire/connector, repair as
necessary.
(2) Replace Driver Airbag Module.
(3) Replace Driver Airbag Module.
Horn does not sound (1) Check fuse 6 in PDC
(2) No Voltage at horn relay
terminals 30 & 86, and fuse is OK.
(3) Open circuit from terminal 85 of
the horn relay to horn switch, X3
circuit.
(4) Defective or damaged horn.
(5) Defective horn switch(1) Replace fuse if blown repair as
necessary.
(2) No voltage, repair the A6 circuit
as necessary.
(3) Repair circuit as necessary.
(4) Voltage at horn when horn switch
is pressed, replace horn.
(5) Replace Driver Airbag Module.
NSHORNS 8G - 3
DIAGNOSIS AND TESTING (Continued)
VEHICLE SPEED CONTROL SYSTEM
CONTENTS
page page
GENERAL INFORMATION
INTRODUCTION......................... 1
DESCRIPTION AND OPERATION
AUTOMATIC SPEED CONTROL OVERSPEED
REDUCTION........................... 2
POWERTRAIN CONTROL MODULE.......... 2
SERVO CABLE.......................... 2
SPEED CONTROL SERVO.................. 1
SPEED CONTROL SWITCHES.............. 1
STOP LAMP SWITCH..................... 2
VACUUM RESERVOIR.................... 3
VEHICLE SPEED AND DISTANCE............ 3
DIAGNOSIS AND TESTING
CHECKING FOR DIAGNOSTIC CODES........ 3
ELECTRICAL TESTS AT POWERTRAIN
CONTROL MODULE..................... 6OVERSHOOT/UNDERSHOOT FOLLOWING
SPEED CONTROL SET................... 3
ROAD TEST............................ 3
SERVO VACUUM TEST.................... 6
SPEED CONTROL ELECTRICAL TEST........ 4
SPEED CONTROL SWITCH TEST............ 6
STOP LAMP SWITCH TEST................ 6
VACUUM SUPPLY TEST................... 8
VEHICLE SPEED SENSOR................. 8
REMOVAL AND INSTALLATION
POWERTRAIN CONTROL MODULE.......... 9
SPEED CONTROL CABLE.................. 9
SPEED CONTROL SERVO.................. 8
SPEED CONTROL SWITCHES.............. 9
STOP LAMP SWITCH.................... 9
VACUUM RESEROIR..................... 10
VEHICLE SPEED SENSOR................ 10
GENERAL INFORMATION
INTRODUCTION
The speed control system is electronically con-
trolled and vacuum operated. The electronic control
is integrated into the powertrain control module,
located next to battery. The controls are located on
the steering wheel and consist of the ON/OFF, SET,
RESUME/ACCEL, CANCEL and DECEL buttons
(Fig. 1).
DESCRIPTION AND OPERATION
SPEED CONTROL SERVO
The servo unit consists of a solenoid valve body,
and a vacuum chamber. The PCM controls the sole-
noid valve body. The solenoid valve body controls the
application and release of vacuum to the diaphragm
of the vacuum servo. The servo unit cannot be
repaired and is serviced only as a complete assembly.
SPEED CONTROL SWITCHES
There are two separate switch pods that operate
the speed control system. The steering-wheel-
mounted switches use multiplexed circuits to provide
inputs to the PCM for ON, OFF, RESUME, ACCEL-
ERATE, SET, DECEL and CANCEL modes. Refer to
the owner's manual for more information on speed
control switch functions and setting procedures.
When speed control is selected by depressing the
ON switch, the PCM allows a set speed to be stored
in RAM for speed control. To store a set speed,
depress the SET switch while the vehicle is moving
at a speed between 30 and 85 mph. In order for the
speed control to engage, the brakes cannot be
applied, nor can the gear selector be indicating the
transmission is in Park or Neutral.
The speed control can be disengaged manually by:
²Stepping on the brake pedal
Fig. 1 Speed Control Switches
NSVEHICLE SPEED CONTROL SYSTEM 8H - 1
SERVO VACUUM TEST
(1) Turn ignition switch to the ON position with-
out starting engine. Activate speed control ON
switch.
(2) Disconnect the four-way electrical connector
and the vacuum harness at the servo (Fig. 3).
(3) Connect a jumper wire from Pin 3 of the servo
to Pin 3 of the wire connector.
(4) Ground Pins 2 and 4 in the servo. Do not con-
nect pin 1.
(5) Connect a hand held vacuum pump to the vac-
uum nipple and apply 10 - 15 inches of vacuum.
(6) If servo pulls cable, replace servo.
(7) Ground Pin 1 on servo.
(8) Check that the throttle cable pulls in and holds
as long as the vacuum pump is connected. After one
minute, check if cable is still holding. If cable does
not hold replace the servo.
(9) Disconnect jumper from pin 3. Cable should
return to rest position. If not, replace servo.
(10) Connect 4 way electrical connector and vac-
uum harness to servo.
SPEED CONTROL SWITCH TEST
Refer to the appropriate Powertrain Diagnostic
Manual for switch test valves.
STOP LAMP SWITCH TEST
(1) Remove the stop lamp switch refer to Stop
Switch Removal/Installation in this section. Discon-
nect connector from stop lamp switch (Fig. 4). Using
an ohmmeter, switch continuity may be checked as
follows:
(2) With switch plunger released, there should be
continuity between Pin 5 and Pin 6.(3) With switch plunger depressed, there should be
continuity:
²Between Pin 1 and Pin 2.
²Between Pin 3 and Pin 4.
(4) If the above results are not obtained, the stop
lamp switch is defective or out of adjustment.
(5) Stop lamp switch adjustment is detailed in
Group 5, Brakes.
ELECTRICAL TESTS AT POWERTRAIN CONTROL
MODULE
(1) Unplug the GRAY 40-way connector from the
Powertrain Control Module (PCM), (Fig. 5).
(2) Remove both steering wheel speed control
switches and disconnect the wire connectors.
Fig. 3 Servo Harness Connector
Fig. 4 Stop Lamp Wiring
Fig. 5 Powertrain Control Module Location
8H - 6 VEHICLE SPEED CONTROL SYSTEMNS
DIAGNOSIS AND TESTING (Continued)
INSTALLATION
Transfer speed control cable to replacement speed
control servo. Reverse the preceding operation.
SPEED CONTROL SWITCHES
REMOVAL
(1) Release hood latch and open hood.
(2) Disconnect battery negative cable.
(3) Remove airbag/horn pad from steering wheel,
refer to Group 8M, Restraint Systems for proper pro-
cedures.
(4) Disconnect wire connector from horn switch,
airbag, and speed control switches.
(5) Remove screws holding speed control switch to
airbag/horn pad (Fig. 11).
(6) Separate speed control switch from airbag/horn
pad.
INSTALLATION
Reverse the preceding operation.
STOP LAMP SWITCH
REMOVAL
Remove the switch from the bracket by depressing
the brake pedal and rotating the switch in a counter-
clockwise direction approximately 30 degrees. Pull
the switch rearward and remove from bracket. Dis-
connect wiring harness connector.
INSTALLATION
Before installing the switch, reset the adjustable
switch plunger by pulling on the plunger head until
the plunger reaches the end of its travel. A ratchet-
ing sound will be heard during this procedure.
Connect the wiring harness to the switch. Mount
the switch into the bracket by holding the switch
with the plunger facing forward in car. There is an
index key on the switch that mates with the bracket
slot at the top of the square hole. Align key and push
switch into square hole in bracket while depressing
the brake pedal. Once the switch is seated in the
hole, rotate clockwise approximately 30 degrees to
lock into place. The switch will automatically adjust
when the pedal is released. Pull back on the pedal to
assure correct adjustment.
SPEED CONTROL CABLE
REMOVAL
(1) Release hood latch and open hood.
(2) On vehicles with 3.3/3.8 L engine, remove air
cleaner resonator. Refer to Group 14, Fuel System for
proper procedure.
(3) Disconnect throttle and speed control cable
ends from throttle body (Fig. 8).
(4) Depress lock tabs holding speed control cable
casing to cable mount bracket (Fig. 12).
(5) Remove tie wrap holding vacuum line, throttle
cable, and speed control cable together.
(6) Remove nuts holding speed control cable case
to servo.
(7) Remove cable case from servo.
(8) Remove hairpin clip holding cable end to servo
diaphragm (Fig. 12).
(9) Remove speed control cable.
INSTALLATION
Reverse the preceding operation.
POWERTRAIN CONTROL MODULE
For Removal/Installation refer to Powertrain Con-
trol Module in Group 14, Fuel Injection System.
USE THE DRB SCAN TOOL TO REPROGRAM
THE NEW PCM WITH THE VEHICLES ORIGI-
NAL IDENTIFICATION NUMBER (VIN) AND
THE ORGINAL VEHICLES MILAGE. IF THIS
Fig. 10 Speed Control Servo
Fig. 11 Speed Control Switches
NSVEHICLE SPEED CONTROL SYSTEM 8H - 9
REMOVAL AND INSTALLATION (Continued)
VEHICLE SPEED CONTROL SYSTEM
CONTENTS
page
GENERAL INFORMATION
INTRODUCTION........................ 1
GENERAL INFORMATION
INTRODUCTION
This group covers both Left-Hand Drive (LHD) and
Right-Hand Drive (RHD) versions of this model.
Whenever feasible, the RHD versions of affected
vehicle components have been constructed as mirror-
image of the LHD versions. While most of the illus-
trations used in this group represent only the LHD
version, the diagnostic and service procedures out-
lined can generally be applied to either version.
Exceptions to this rule have been clearly identified as
LHD or RHD, if a special illustration or procedure
was/is required.
The speed control system used with the 2.5L diesel
engine is basically identical to the system used with
gasoline powered engines. Features unique to the
diesel engine will be covered in this section.
²Models equipped with the 2.5L diesel engine do
not use a vacuum reservoir to retain engine vacuum
for speed control operation. There are no vaccum-op-
erated speed control servos used in vehicles with the
2.5L diesel engine.
²The range of the speed control system operation
is restricted to speeds between 56 km/h (35 MPH) to
145 km/h (90 MPH).
²Inputs to the MSA that allow speed control oper-
ation are from the vehicle speed sensor and the
Speed Control Switch.²Two separate speed control switch modules are
mounted on the steering wheel to the left and right
side of the driver's airbag module. Switch features
are:
a. Within the two switch modules, fivemomen-
tarycontact switches, supporting seven different
speed control functions are used.
b. The outputs from these switches are filtered
into one input. The MSA determines which output
has been applied throughresistive multiplexing.
The input circuit voltage is measured by the MSA
to determine which switch function has been
selected.
c. A speed control indicator lamp, located on the
instrument panel cluster is energized by the MSA
via the CCD Bus. This occurs when speed control
system power has been turned ON, and the engine
is running.
d. The two switch modules are labeled: ON/OFF,
SET, RESUME/ACCEL, CANCEL and COAST.
Refer to the owner's manual for more information
on speed control switch functions and setting pro-
cedures. The individual switches cannot be
repaired. If one individual switch fails, the switch
module must be replaced.
NS/GSVEHICLE SPEED CONTROL SYSTEM 8H - 1