instrument cluster system DODGE TRUCK 1993 Service Repair Manual

•

BRAKES
BRAKES
5 - 1

CONTENTS

page

BENDIX
DISC
BRAKE
37

BRAKE
ADJUSTMENTS-BRAKE BLEEDING .. 7

BRAKE
DIAGNOSIS
3

CHRYSLER
DISC
BRAKE
27
DRUM
BRAKES-ELEVEN
INCH 46
DRUM
BRAKES-TWELVE
INCH 50

GENERAL
INFORMATION 1
MASTER
CYLINDER-COMBINATION
page

VALVE-BRAKE
LINES 10

PARKING
BRAKES
56

POWER
BRAKE
BOOSTER-BRAKE
PEDAL .. 20

POWER
BRAKE
VACUUM PUMP-DIESEL
ENGINE
...22

REAR
WHEEL ANTILOCK (RWAL)
BRAKES
.. 59

SPECIFICATIONS
65

GENERAL INFORMATION
INDEX

page

Antilock
Rear
Wheel
Brakes
1
Brake
Components 1

BRAKE
COMPONENTS
AD models are equipped with front disc and rear
drum brakes. Power assist brakes and rear wheel an­
tilock brakes are standard equipment on all models. A dual reservoir master cylinder and single or dual
diaphragm, vacuum operated power brake booster is
used for all applications. Models with the Cummins
diesel engine option are also equipped with a vacuum
pump assembly to operate the power brake booster. Front disc brake units consist of single piston, slid-
ing-type calipers with semi metallic brakeshoe lin­ ing. Vented disc brake rotors are used on all models. Bendix calipers are used on 4-wheel drive models
and on diesel engine models. Chrysler disc brake cal­
ipers are used for all other applications. Rear drum brakes are dual shoe units with an au­
tomatic adjustment mechanism. Bendix and Chrysler drum brake assemblies are used. A combination valve is used on all models. The
valve consists of a front brake metering (hold-off)
valve and a front/rear pressure differential switch. A red, brake indicator and warning light is used to
alert the driver if a pressure differential exists be­
tween the front and rear hydraulic systems. The light also alerts the driver when the parking brakes
are applied. The light is located at the left side of the
instrument cluster. An additional indicator light is used for the anti-
lock system. This light is amber and is located in the
page

Brake
Fluid/Lubricants/Cleaning
Solvents
1

Brake
Safety Precautions 2
same side of the instrument cluster as the red indi­
cator light. The antilock light alerts the driver if a system fault occurs.

ANTILOCK
REAR
WHEEL
BRAKES
All AD models are equipped with antilock rear
brakes. The system is designed to retard wheel lockup during periods of high wheel slip when brak­
ing. Retarding wheel lockup is accomplished by modu­
lating fluid pressure to the wheel brake units. Refer
to the Rear Wheel Anti-Lock Brake section for oper­ ation and service information.

BRAKE
FLUID/LUBRICANTS/CLEANING SOLVENTS Recommended fluid for all AD models is Mopar
brake fluid or equivalent meeting SAE J1703 and DOT 3 standards. Use Mopar multi mileage grease to lubricate cali­
per slide surfaces, drum brake pivot pins and shoe contact points on the backing plates. Use GE 661 or
Dow 111 silicone grease (or equivalent) on caliper
bushings and slide pins. Use fresh brake fluid or Mopar brake cleaner to
clean or flush brake system components. These are
the only cleaning materials recommended.

• • ^ ^ ^ INSTRUMENT PANEL AND GAUGES 8E - 1
CONTENTS

page
CLUSTER AND GAUGE SERVICE PROCEDURES . 12
CLUSTER AND GAUGE TEST PROCEDURES .. i
GENERAL INFORMATION . 1
page

MESSAGE CENTER-DIESEL ENGINE ........ 4
MESSAGE CENTER-GAS ENGINE .......... 3

SWITCH
AND PANEL COMPONENT SERVICE . 16
GENERAL
INFORMATION
INDEX

page

Generator
Indicating
System
2
Distance
Sensor
2

Electronic
Digital
Clock
3

Fuel
Level
Indicating
System
1
page

Malfunction
Indicator
(Check
Engine)
3

Oil
Pressure
Warning
Lamp
................. 2
Speedometer/Odometer
System
2

Temperature
and Oil
Indicating
System
......... 2
D-body trucks have an instrument cluster which
includes gauges for fuel level, coolant temperature,
oil pressure, and charging system voltage (Fig. 1).
When the ignition switch is in the OFF position all
the gauges will show a reading except the voltage gauge. However, the readings are only accurate
when the ignition switch is in the ON position.
The cluster also includes warning lamps for:
• seat belt warning
• low oil pressure
• high beam
• left and right turn signals
• check engine. J908E-66

Fig.
11nstrument
Cluster
FUEL LEVEL INDICATING SYSTEM (FIG. 2)
A hinged float arm in the fuel tank raises or lowers
depending on the fuel level. The float arm contacts a
variable resistor in the gauge sending unit. This pro­
vides a change of resistance in the fuel gauge circuit
with any up or down movement of the float. This sender
resistance is shown as fuel level on the gauge. Resistance is greatest when the fuel level in the
tank is low and the float arm drops. With high resis­
tance current flow is low and consequently positions
the instrument panel gauge pointer to low.
Resistance in the circuit is at a minimum when the
tank is full and the float arm is raised. With resis­
tance at a minimum, current flow is high registering
full on the instrument panel gauge.
12
VOLTS
TO

GAUGE
IP

FUEL
TANK

SENDING
UNIT

FLOAT

SENDING
UNIT
1:
1
j
^
fCONNECTOR

!g|yj-»—
FUEL

GAUGE

FUEL

TANK

J098E-47

Fig.
2
Fuel
Level
Indicating
System

INSTRUMENT PANEL AND GAUGES

8E
- 2
INSTRUMENT PANEL
AND
GAUGES

•
TEMPERATURE AND
OIL
INDICATING SYSTEM
(FIG.
3) The operation of the temperature and oil pressure
indicating systems are identical. In the temperature
system the sending unit resistance varies in direct
relationship to the temperature of the coolant. When the engine is cold, the resistance of the tem­
perature sending unit is high and a cold temperature
will be indicated on the gauge. When the engine is hot, the resistance of the tem­
perature sending unit is low and a hot temperature
will be indicated on the gauge. In the oil pressure indicating system the sending
unit resistance is actuated by a diaphragm as the oil
pressure increases or decreases. Low oil pressure causes high resistance. High pressure causes low re­
sistance. 12
VOLTS
TO
GAUGE
TEMPERATURE/
OIL GAUGE
TEMPERATURE/OIL SENDING
UNIT
J908E-48
Fig. 3 Temperature/Oil indicating System

OIL
PRESSURE
WARNING LAMP
The oil pressure warning switch, mounted on the
engine, is controlled by engine oil pressure. When engine oil pressure is normal, the switch is
held in the OFF or OPEN position. This stops cur­
rent from flowing to the oil pressure warning lamp
on instrument panel. When the engine oil pressure is low, the switch is
in the ON or CLOSED position. This allows current
to flow to the oil pressure warning lamp in the in­ strument cluster causing the warning lamp to illumi­

nate.
GENERATOR
INDICATING
SYSTEM
(FIG. 4)
The voltmeter gauge senses the voltage of the elec­
trical system.
VOLTAGE
/*

GAUGE
P/
J908E-49 Fig. 4 Generator Indicating System

SPEEDOMETER/ODOMETER SYSTEM
The speedometer/odometer system consists of an
electric speedometer and pushbutton reset odometer
mounted in the cluster. The system also includes the
wire harness from the cluster to the distance sensor at the transmission, and the adapter and pinion in
the transmission. The speedometer/odometer has the same appearance as a conventional version but it
eliminates the cable-driven mechanical system. A signal is sent from a transmission mounted distance
sensor to the speedometer/odometer circuitry through
the wiring harness. By eliminating the speedometer cable, instrument cluster service and removal is im­
proved. Refer to Group 21 - Transmission for select­ ing the proper pinion, and selecting and indexing the
proper adapter.

DISTANCE
SENSOR

DISTANCE SENSOR TEST For testing of the distance sensor and related com­
ponents refer to the Vehicle Diagnostics Test Proce­ dure Manual.
DISTANCE SENSOR REMOVAL AND INSTALLATION (1) Remove harness connector from sensor. Be sure
weather seal stays on harness connector. (2) Remove sensor by loosening sensor coupling
nut from the pinion gear adapter until sensor is free (Fig. 5).
(3) To install the sensor, reverse the removal pro­
cedures. Tighten coupling nut to 17 N»m (150 in. lbs.)

•

INSTRUMENT PANEL
AND
GAUGES
8E - 5
CLUSTER
AND
GAUGE TEST
PROCEDURES

INDEX
page
Fuel Gauge
Circuit
Test
9

Fuel Tank Sending
Unit
Test
5

Oil Pressure Gauge
Circuit
Test
..............
9
Sending
Unit
(Sensor) Test
5
page
Speedometer
10

Temperature
Gauge
Circuit
Test
8
Voltage Gauge
Circuit
Test
10

Warning Lamp System Tests
6

CAUTION:
Disconnect
battery
negative cable,
in
en­

gine compartment, before servicing instrument panel. When power
is
required
for
test purposes,
connect
battery
cable
(for
test only).

Disconnect battery negative cable after test
and before continuing service procedures.

SENDING
UNIT
(SENSOR) TEST
When
a
problem occurs with
a
cluster gauge,
be­

fore disassembling
the
cluster
to
check
the
gauge, check
for a
defective sending unit (sensor)
or
wiring.
(1) Sending units
and
wiring
can be
checked
by

grounding
the
connector leads,
at the
sending unit,
in
the
vehicle.

CAUTION:
When connecting
an
input
terminal
to

ground,
Do Not
leave
the
connection grounded
for
more than
a
few
seconds.

(2) With
the
ignition
in the ON
position;
a

grounded input will cause
the oil,
fuel
or
tempera­
ture gauge
to
read
at or
above maximum.
FUEL TANK SENDING
UNIT
TEST

(1) Disconnect wire from terminal
on
fuel tank
sending unit (Fig.
1).

FUEL PUMP SUPPLY
INPUT
TO
GAUGE
SENDING
UNIT
GROUND
FUEL PUMP GROUND
J928E-49

Fig.
1
Fuel
Tank
Sending
Connector
Terminals
(2) Connect wire
to a
known good sending unit.
(3) Connect
a
jumper wire between sending unit
fuel pick
up
tube
and a
good ground.
(4) Check fuel gauge
as
described
in
following

steps.
Allow
at
least three minutes
at
each test point
for gauge
to
settle. Lightly tapping instrument clus­
ter
may
help position pointer.

FUEL GAUGE SYSTEM DIAGNOSIS
FUEL GAUGE SYSTEM DIAGNOSIS FUEL GAUGE

DOES
NOT

READ
FULL FAULTY PRINTED
CIRCUIT BOARD FUEL GAUGE
INOPERATIVE OR ERRATIC FUEL GAUGE
INACCURATE

E

1

I

CHECK
FAULTY WIRING
OR
TANK DEFORMED
TANK
NOT
FULL COMPONENTS
CHECK
CHECK
ALL WIRING INCLUDING GROUND
i

FAULTY FUEL GAUGE SENDING
UNIT
i 1
FUEL
C
1
DOES
1
READ
1
pAUGE
I

>N0?
1

EMPTY
1

r

TANK
NOT
EMPTY
CHECK
PROPER
ALIGNMENT
OF PICKUP AND

SENDER
ASSEMBLY.

REFER
TO
GROUP
14
FAULTY FUEL
GAUGE

J908E-74

8E
- 6
INSTRUMENT PANEL
AND
GAUGES

•
(5)
Clip float arm of sending unit to its empty stop
(Fig. 2) and turn ignition key to ON position. The
gauge should read Empty, plus one pointer width, or
minus two pointer widths.
(6) Move and clip sending unit float arm to full

stop.
The gauge should read Full, or above.
Fig. 2 Fuel Tank Sending Unit Test
RESULTS (1) If fuel gauge does not meet specifications, check
following items as possible causes; (a) Wiring and connections between the gauge
sending unit and multiple connector. (b) Wiring and connections between multiple
connector and printed circuit board terminals.
(c) Circuit continuity between printed circuit
board terminals and gauge terminals.
If these items check okay, fuel gauge is defective
and must be replaced.
(2) If the fuel gauge meets specifications check fuel
tank and original installed fuel tank sending unit as follows:
(a) Carefully remove fuel tank sending unit from
tank.
(b) Connect sending unit wire and jumper wire
as described in the procedure.
(3) If fuel gauge now checks within specifications,
originally installed sending unit is electrically okay,
check following as possible cause:
(a) Ground strap from sending unit to fuel line
for continuity. (b) Sending unit deformed. Make sure sending
unit float arm moves freely and pick up tube is not
bent so that it contacts bottom of tank. Inspect float for any signs of damage or leaks. (c) Sending unit improperly installed. Install
properly.
(d) Mounting flange on fuel tank for sending
unit deformed. Feel for interference fit of sending
unit to bottom of tank. It is permissible to bend
pick up tube down a little near mounting flange to gain interference fit.
(e) Fuel tank bottom deformed causing improper
positioning of sending unit pick up tube. Replace or
repair tank and recheck sending unit. Refer to Fuel
Tank Section of Group 14 - Fuel System.

WARNING
LAMP
SYSTEM
TESTS
LOW
OH.
PRESSURE WARNING LAMP CIRCUIT
TEST
The low oil pressure warning lamp will illuminate
when the ignition key is turned to the ON position.
The lamp also illuminates if the engine oil pressure drops below a safe oil pressure level.
To test the system turn ignition key to the ON po­
sition.
If the lamp fails to light, inspect for a broken or
disconnected wire at the oil pressure combination
unit. The combination unit is located at the rear of
the engine (Fig. 3). If the wire at the connector checks good, pull connector loose from the switch and
with a jumper wire ground connector to the engine (Fig. 4). With the ignition key turned to the ON po­
sition check the warning lamp. If lamp still fails to
light, inspect for a burned out bulb or disconnected
socket in the cluster.
If light comes on, proceed and start engine. If the
lamp remains on, immediately turn engine off and
check engine oil pressure according to procedures as
outlined in Group 9 - Engine of this manual. If the
oil pressure meets specifications, check for a
grounded wire and/or replace the oil pressure send­
ing unit (refer to combination oil unit test). Fig. 3 Oil Pressure Sending Unit—Gas Engine

•

AUDIO
SYSTEMS
8F - 7
SERVICE
PROCEDURES

RADIO
REPLACEMENT

REMOVAL
(1) Disconnect negative cable from battery.

CAUTION:
Map
lamp
must
be
removed
to
prevent

damage
to instrument panel.
(2) Remove 2 screws and the map lamp (if
equipped) (Fig. 9). (3) Remove 6 screws attaching I/P bezel to the in­
strument panel. Be sure the screw below the Heat-
er/C control is removed.

CLUSTER
BEZEL
J938E-51
Fig.
9 Instrument
Cluster
Bezel

(4) Remove 2 mounting screws from front of radio
(Fig. 10).
(5) Pull radio out of instrument panel and discon­
nect wiring and antenna.

(6)
Remove screw from ground strap.
RF431

Fig.
10 Radio to Instrument
Panel
Mounting
INSTALLATION

(1) Install ground strap.
(2) Install wiring and antenna. (3) Insert radio into panel and install mounting
screws.
(4) Install instrument cluster bezel.
(5)
Install map lamp, if equipped.
(6) Connect negative cable to battery.

DOOR
MOUNTED
SPEAKER

REMOVAL
(1) Remove remote control handle.
(2) Remove window regulator handle, if equipped.
(3) Remove pull strap if equipped.
(4) Remove screw at top of armrest.

(5)
Using a trim stick or other suitable flat tool,
gently pry trim panel away from door.
(6) Remove screws holding speaker (Fig. 11).
(7) Disconnect speaker leads.
(8) Remove speaker.
Fig.
11
Door
Mounted
Speaker

INSTALLATION

(1) Connect leads to speaker.
(2) Position speaker into place, install mounting
screws and tighten securely.
(3) Install door trim panel.

REAR
SPEAKER
-
STANDARD
CAB PICKUP

REMOVAL
(1) Remove grille and speaker assembly to pillar
mounting screws (Fig. 12). (2) Pull speaker and grille away from pillar and
disconnect wiring.
(3) Remove speaker to grille retaining nuts (2).

INSTALLATION
(1) Position speaker onto studs of speaker grille
and install nuts.
(2) Install wiring harness connector on speaker.
(3) Position speaker and grille on pillar and install
mounting screws.

•

VEHICLE
SPEED
CONTROL SYSTEM
8H - 7
TEST
PROCEDURES

INDEX

page

Checking
for
Diagnostic
Trouble
Code
7

General
Information
7
Inoperative
System
7

Road
Test
7

Speed
Control
Cable Adjustment—Diesel Engine
. 9

Speed
Control
Cable
Attachment
10

GENERAL
INFORMATION

Before starting diagnosis and repair procedures for
a speed control malfunction, verify that the speed
control wire harness is properly connected to all con­ nectors. Refer to Diagnosis Chart.

ROAD
TEST
Road test vehicle to verify reports of speed control
system malfunction. The road test should include at­
tention to the speedometer. Speedometer operation should be smooth and without flutter at all speeds. Flutter in the speedometer indicates a problem
which might cause surging in the speed control sys­
tem. The cause of any speedometer deficiencies should be corrected before proceeding.

INOPERATIVE SYSTEM
If road test verifies a system problem and the
speedometer operates properly, check for:
• loose electrical and vacuum connections at the
servo.

• check for correct installation of the vacuum check
valve in the hose from servo to vacuum source (Gas
Engine Only). The word VAC on the valve must
point toward the vacuum source. • corrosion that should be removed from electrical
terminals and a light coating of Mopar Multi-Pur­
pose Grease, or equivalent, applied. • secure attachment of both ends of speed control ca­

ble.

CHECKING
FOR DIAGNOSTIC TROUBLE CODE
(1) When trying to verify a speed control system
electrical problem, use a DRB II Scan Tool to find
the cause. Refer to Powertrain Diagnostic Procedures manual. If the DRBII is not available, the Diagnostic Trou­
ble Code (DTC) may be determined with the follow­ ing method: (a) With key inserted in ignition switch, cycle
switch to ON position 3 times. On third cycle, leave
switch in ON position. (b) After switch has been cycled 3 times, observe
Malfunction Indicator Lamp (CHECK ENGINE) on instrument cluster. If a DTC is present, the code
page

Speed
Control
Cable Attachment—Servo
10

Stop Lamp Switch Test
9

Vacuum Supply Test
....................... 9

Vehicle Speed
Control
Switch Test
. 9

Vehicle Speed
Control
System
Electrical
Tests
... 7

Vehicle Speed Sensor Test
7
will be displayed in a series of flashes representing
digits.
Three flashes in rapid succession, a slight
pause, then 4 flashes in rapid succession would in­ dicate DTC 34.
(2) If a DTC 34 is observed, perform the tests in
the sections Electrical Tests at Servo and Electrical
Tests at Powertrain Control Module.
If a DTC 15 is observed, perform the test for a
faulty Vehicle Speed Sensor.
(3) If a fault code 11 is observed (Diesel only), per­
form the test for a faulty engine speed sensor. Refer
to the Powertrain Diagnostics Procedures Manual.
(4) Correct any problems found when performing
these tests and recheck for DTC if changes were made.

VEHICLE SPEED SENSOR TEST
For testing of the Vehicle Speed Sensor and related
components refer to the Powertrain Diagnostic Proce­
dures manual.

VEHICLE SPEED CONTROL SYSTEM ELECTRICAL
TESTS
Vehicle speed control systems may be tested using
two different methods. One involves the use of the DRBII Scan Tool. If this test method is desired,
please refer to the Powertrain Diagnostic Procedures manual. The other test method uses a voltmeter. The volt­
meter method is described in the following tests.
If any information is needed concerning wiring, re­
fer to Group 8W - Wiring Diagrams.

CAUTION:
When test probing
for
voltage
or
conti­nuity
at
electrical
connectors, care must
be
taken
not
to
damage connector, terminals,
or
seals.
If

these components
are
damaged,
intermittent
or
complete system
failure
may
occur.
ELECTRICAL
TESTS
AT
SERVO
(1) Turn ignition switch to ON position.
(2) Push speed control switch to ON position.
(3) Connect the negative lead of a voltmeter to a
good chassis ground near the servo.

8W
- 38
WIRING
DIAGRAMS

• Wiring Diagram Name Sheet Number

EMCC
Relay
11

EMCC
Solenoid
11

Ground
11

EMCC
Relay
with Gas
Engine
11,16

EMCC
Solenoid
with Gas
Engine
11,12

Engine
Oil
Pressure Sending
Unit
.27,28
Engine
Starter
Motor
7,9
Engine
Starter
Relay
.7,9

Engine
Starter
System 1,7,8,9 Back-Up Lamp
Switch
.7,9

Bypass
Jumper
(Clutch
Pedal
Position)
8

Clutch
Pedal
Position
Switch
8

Fuse
. 7,9

Motor
7,9
Park/Neutral
Position
Switch
. .7,9

Relay
7,9

Engine Temp Sending
Unit
.
.27,28
Flasher-Hazard Warning
.56
Flasher-Turn Signal
56

Four Wheel
Drive
Indicator
Lamp
13

Front
End
Lighting
. .
.43,44

Front
End
Lighting
(Canada) 45,46

Fuel
Gauge
81,82

Fuel
Tank Gauge
Level
Sending
Unit
Diesel Engine
77

Fuel
Tank Gauge
Level
Sending
Unit
with Gas
Engine
78
Fuel
Heater
Diesel Engine
24

Fuel
Solenoid Diesel Engine
.24

Fuse
Application
Chart
1,2

Fuse
Block Module
and
Relay Bank
82

Fuses
Fuse
1 2,36
Fuse
2
.........
2,10,12,13,14,58,77,78

Fuse
3
2,7,9,10,39
Fuse
4
1,30,47

Fuse
5
1,77,78
Fuse
6
......
.1,73

Fuse
7
1,10,52

Fuse
8
.2,10,61,63
Fuse
9
.2,10,31,33,56

Fuse
10
.2,10,54,55

Fuse
11
2,10,66,67,69

Fuse
12
2,10,71
Fuse
13 1,56
Fuse
14
1,47,52,61,63

Fuse
15
1,49,51,52,61,63,75
Fusible Links 1,2,3,4,5,6,21

Gas
Engine
Wiring
Connector
89

Gauge-Fuel .77,78

Generator
.4,6

Glove
Box
Lamp
Switch
52

Hazard Warning System
. .56
Headlamp Dimmer
Switch
47

Headlamp
Switch
1,47

Headlamp
Switch
Controlled
Interior
Lamps
Headlamps 43,44,

Heated
Rear Window
(Sport
Utility)
Heater
Motor
Resistor

Heater
System Wiring Diagram Name Sheet Number
Horn System
30
Identification
Lamps-Dual Rear Wheels
41,42

Identification
Lamps-Roof Mounted
. 40
Ignition
Coil
.16

Ignition
Switch
.2,10

Ignition
Switch
System
10

Ignition
System (Gas Engine)
.........
.15,16,17,18,19,20
Automatic
Shut Down Relay
.16
Camshaft
Position
Sensor
20

Crankshaft
Position
Sensor
.18

Data
Link
Connector
* . . .17
Engine Coolant Temp
Sensor
20

EVAP
Purge Solenoid
16
Exhaust Gas
Recirculation
Solenoid
16
Fuel
Pump Relay
.16

Heated
Oxygen
Sensor
. . . 17

Idle
Air
Control
Motor
.19

Ignition
Coil
.15
Injectors
.15

Intake
Air
Temp
Sensor
. .20

Map
Sensor
. .20
Powertrain
Control
Module .15,16,17,18,19,20

Throttle
Position
(Sensor)
.18

Vehicle
Speed
Sensor
.20

Ignition
Time
Delay Relay
49

Injectors
.15 Intermittent
Wiper
System .53,54
Control
Unit
.54 Intermittent
Windshield
Wiper
Motor
54

Windshield
Washer Pump
Motor
53

Wiper
Switch
53

Key-In
Switch
49

Key-In Warning Buzzer 77,78
Lamps
Air-Conditioning
and
Heater
Switch
Lamp
48

Ash
Receiver .48,52 Back-Up Lamps
......
79,80,81
Cargo Lamp
.
.49,50 Clearance Lamps-Dual Rear Wheels .41,42
Clearance Lamps Roof Mounted
.40

Cluster
Illumination
Lamps
.
.57,58,59
Dome Lamp
50,51

Four Wheel
Drive
Indicator
.13

Glove
Box
Lamp
52
Headlamp-Left
43,45 Headlamp-Right 44,46
Headlamp
Switch
Controlled
Interior
Lamps
. 48

Heater
Switch
Lamp
.48
High Beam
Indicator
Lamp
.59

Identification
Lamp
.
.40,41

Ignition
Switch
Lamp
.49
Instrument
Panel
Illumination
Lamps
.
.57,58,59
License Lamp
. . . 80
.
.48 Low
Engine
Oil
Pressure Lamp
59

45,46
Map
Lamp
49

.
.39
Parking
Lamp-Left
Front
43,45
66,67 Parking Lamp-Right
Front
44,46 .
.66
Rear
End
Lighting
System .79,80,81

14 - 38
FUEL SYSTEM

•
Fig.
17 Ignition Coil—5.9L
HDC-Gas
Engine

SHIFT INDICATOR-PCM
OUTPUT
Vehicles equipped with manual transmissions have
an Up-Shift indicator lamp. The lamp is controlled
by the powertrain control module (PCM). The lamp illuminates on the instrument panel to indicate when
the driver should shift to the next highest gear for
best fuel economy. The PCM will turn the lamp off after 3 to 5 seconds if the shift of gears is not per­
formed. The up-shift light will remain off until vehi­ cle stops accelerating and is brought back to range of
up-shift light operation. This will also happen if ve­
hicle is shifted into fifth gear. The indicator lamp is normally illuminated when
the ignition switch is turned on and it is turned off
when the engine is started up. With the engine run­
ning, the lamp is turned on/off depending upon en­
gine speed and load.

SPEED
CONTROL-PCM
OUTPUT
Speed control operation is regulated by the power-
train control module (PCM). The PCM controls the
vacuum to the throttle actuator through the speed
control vacuum and vent solenoids. Refer to Group
8H for Speed Control Information.

TACHOMETER—PCM
OUTPUT
The powertrain control module (PCM) supplies en­
gine rpm values to the instrument cluster tachome­ ter. Refer to Group 8E for tachometer information.

OPEN
LOOP/CLOSED LOOP MODES
OF

OPERATION

As input signals to the powertrain control module
(PCM) change, the PCM adjusts its response to the
output devices. For example, the PCM must calculate
different injector pulse width and ignition timing for
idle than it does for wide open throttle (WOT). There
are several different modes of operation that deter­
mine how the PCM responds to the various input sig­
nals.
MODES

• Open Loop
• Closed Loop During Open Loop modes, the powertrain control
module (PCM) receives input signals and responds
only according to preset PCM programming. Input
from the oxygen (02) sensor(s) is not monitored dur­
ing Open Loop modes.
During Closed Loop modes, the PCM will monitor
the oxygen (02) sensor input. This input indicates to
the PCM whether or not the calculated injector pulse width results in the ideal air-fuel ratio. This ratio is 14.7 parts air-to-1 part fuel. By monitoring the ex­
haust oxygen content through the 02 sensor, the
PCM can fine tune the injector pulse width. This is done to achieve optimum fuel economy combined
with low emission engine performance.
The fuel injection system has the following modes
of operation:
• Ignition switch ON • Engine start-up (crank)
• Engine warm-up
• Idle
• Cruise • Acceleration
• Deceleration
• Wide open throttle (WOT)
• Ignition switch OFF The ignition switch On, engine start-up (crank),
engine warm-up, acceleration, deceleration and wide
open throttle modes are Open Loop modes. The idle and cruise modes, (with the engine at operating tem­
perature) are Closed Loop modes.

IGNITION
SWITCH
(KEY-ON)
MODE
This is an Open Loop mode. When the fuel system
is activated by the ignition switch, the following ac­
tions occur:
• The powertrain control module (PCM) pre-posi-
tions the idle air control (IAC) motor. • The PCM determines atmospheric air pressure
from the MAP sensor input to determine basic fuel strategy.
• The PCM monitors the engine coolant temperature sensor input. The PCM modifies fuel strategy based
on this input.
• Intake manifold charge air temperature sensor in­
put is monitored.
• Throttle position sensor (TPS) is monitored. • The auto shut down (ASD) relay is energized by
the PCM for approximately three seconds. • The fuel pump is energized through the fuel pump
relay by the PCM. The fuel pump will operate for ap­
proximately one second unless the engine is operat­ ing or the starter motor is engaged.
• The 02 sensor(s) heater element is energized
through the fuel pump relay. The 02 sensor(s) input

24
- 38
HEATING
AND AIR
CONDITIONING

INSTALLATION
(1) Remove and replace the aluminum N-gaskets
(1 on evaporator plate and 1 on plumbing plate). (2) Remove sealing cap from H-valve control head
side sealing surface and hold it against evaporator
sealing plate. DO NOT scratch sealing surface. In­
stall the Torx Drive screws and tighten to 11 N-m (100 in. lbs.) torque.
(3) Remove sealing cap from plumbing side sealing
surface and hold plumbing up to valve. Install the
bolt and tighten to 23 N*m (200 in. lbs.) torque.
(4) Connect wires to electronic temperature cycling
switch. (5) After expansion valve is installed and system
charged and leak checked, repeat performance check.

AIR CONDITIONER DISTRIBUTION AND SPOT
COOLER
DUCTS-CENTER

REMOVAL (1) Disconnect the negative cable from the battery.
(2) Open glove box past stops.
(3) Remove right upper air duct by removing
mounting screw and pulling duct out through glove
box opening (Fig. 9).
(4) Remove instrument panel center brace.
(5) Remove right kick pad.
(6) Remove right instrument panel pivot bolt.
(7) Remove instrument panel cluster.
(8) Disconnect shift indicator cable.
(9) Lower steering column.
(10) Remove steering column studs.
(11) Remove radio.
(12) Remove mounting screws and remove scoop
connecting heater unit to center distribution duct. (13) Remove mounting screws and remove center
distribution duct by pulling bottom of instrument
panel out and dropping duct out (Fig. 9).

INSTALLATION
(1) Position the center distribution duct through
the bottom of instrument panel (Fig. 9). Install mounting screws.
(2) Position the scoop connecting heater unit to
center distribution duct. Install mounting screws.
(3) Install radio.
(4) Install steering column studs.
(5) Place steering column into position.
(6) Connect shift indicator cable.
(7) Install instrument panel cluster.
(8) Install right instrument panel pivot bolt.
(9) Install right kick pad.
(10) Install instrument panel center brace.
(11) Position the duct in through glove box open­
ing (Fig. 9). Install mounting screw. (12) Close glove box.
(13) Connect the negative cable to the battery.
AIR CONDITIONER DISTRIBUTION AND SPOT

COOLER
DUCTS-RIGHT BI-LEVEL

REMOVAL (1) Disconnect the negative cable from the battery. (2) Open glove box past stops.
(3) Remove right upper air duct by removing
mounting screw and pulling duct out through glove
box opening (Fig. 9).

INSTALLATION
(1) Position the right upper air duct through glove
box opening (Fig. 9). Install mounting screw.
(2) Close glove box.
(3) Connect the negative cable to the battery.

AIR CONDITIONER DISTRIBUTION AND SPOT
COOLER
DUCTS-LEFT BI-LEVEL

REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Remove instrument panel cluster.
(3) Disconnect shift indicator cable.
(4) Remove heater control.
(5) Remove mounting screws and cover that re­
tains instrument panel wiring and let wiring hang

free.

(6) Remove mounting screw and slide left air duct
out through instrument cluster opening (Fig. 9).

INSTALLATION
(1) Slide left air duct in through instrument clus­
ter opening (Fig. 9). Install mounting screw. (2) Position the cover that retains instrument
panel wiring. Install mounting screws.
(3) Install heater control.
(4) Connect shift indicator cable.
(5) Install instrument panel cluster.
(6) Connect the negative cable to the battery.

AIR OUTLET
ASSEMBLIES
RIGHT
SIDE
Both right side outlets are held in place with
spring loaded retaining clips.
REMOVAL (1) With outlet facing out and louver vanes open,
grasp adjusting vane with fingers.
(2) Pull smoothly and firmly to unseat clips and
complete removal toward rear of vehicle.

INSTALLATION
(1) Position outlet assembly in panel opening, f
making sure lettering stamped TOP is up (ribs on
housing match notches on instrument panel).
(2) Press housing assembly until both retaining
clips lock into place.