oil temperature JEEP YJ 1995 Service And Owner's Guide

THROTTLE POSITION SENSOR
From the Powertrain Control Module (PCM), cir-
cuit K6 supplies 5 volts to the throttle position sen-
sor (TPS). Circuit K6 connects to cavity 6 of the
PCM.
Circuit K22 delivers the TPS signal to the PCM.
Circuit K22 connects to cavity 22 of the PCM.
The PCM provides a ground for the throttle posi-
tion sensor signal (circuit K22) through circuit K4.
Circuit K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
Refer to Group 14 for throttle position sensor oper-
ation.
Circuit K6 splices to supply 5 volts to the manifold
absolute pressure sensor.
Circuit K22 splices to the transmission control
module.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
MANIFOLD ABSOLUTE PRESSURE SENSOR
From the Powertrain Control Module (PCM), cir-
cuit K6 supplies 5 volts to the manifold absolute
pressure (MAP) sensor. Circuit K6 connects to cavity
6 of the PCM.
Circuit K1 delivers the MAP signal to the PCM.
Circuit K1 connects to cavity 1 of the PCM.
The PCM provides a ground for the MAP sensor
signal (circuit K1) through circuit K4. Circuit K4 con-
nects to cavity 4 of the PCM.
HELPFUL INFORMATION
Refer to Group 14 for MAP sensor operation.
Circuit K6 splices to supply 5 volts to the throttle
position sensor.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
INTAKE AIR TEMPERATURE SENSOR
The intake air temperature sensor provides an in-
put to the Powertrain Control Module (PCM) on cir-
cuit K21. Circuit K21 connects to cavity 21 of the
PCM.From circuit K21, the intake air temperature sen-
sor draws voltage from the PCM. The sensor is a
variable resistor. As intake air temperature changes,
the resistance in the sensor changes, causing a
change in current draw.
The PCM provides a ground for the intake air tem-
perature sensor signal (circuit K21) through circuit
K4. Circuit K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
PARK/NEUTRAL POSITION SWITCH
When closed, the case-grounded park/neutral posi-
tion switch provides a ground path on circuit T41 for
the coil side of the starter motor relay. Circuit A41
from the ignition switch provides battery voltage to
the coil side of the relay.
Circuit T41 splices to cavity 30 of the PCM. The
park/neutral position switch provides an input to the
Powertrain Control Module (PCM).
TACHOMETER SIGNAL
The PCM supplies the signal for the tachometer on
circuit G21. Circuit G21 connects to cavity 43 of the
PCM.
MALFUNCTION INDICATOR LAMP (MIL)
The Powertrain Control Module (PCM) provides
ground for the instrument cluster malfunction indica-
tor lamp on circuit G3. The MIL displays the mes-
sage CHECK ENGINE when illuminated. Circuit
F87 provides voltage for the lamp. Circuit G3 con-
nects to cavity 32 of the PCM.
DATA LINK CONNECTOR
Circuit F12 supplies battery voltage to the data
link connector. Circuit F12 originates at fuse 11 in
the Power Distribution Center.
Circuit D20 connects to cavity 45 of the PCM. Cir-
cuit D20 is the SCI receive circuit for the PCM.
Circuit D21 connects to cavity 25 of the PCM. Cir-
cuit D21 is the SCI transmit circuit for the PCM.
Circuit Z11 provides ground for the data link con-
nector. Circuit Z11 also connects to cavity 5 of the
PCM.
8W - 30 - 4 8W-30 FUEL/IGNITIONÐXJ-RHDJ

HELPFUL INFORMATION
²If the system loses ground for the Z11 circuits at
the right rear of the engine, the vehicle will not op-
erate. Check the connection at the ganged-ground cir-
cuit eyelet.
²Circuit F12 splices to supply battery voltage to the
vehicle speed control switch, back-up lamp switch,
A/C compressor clutch relay, windshield washer fluid
level sensor and radiator fan relay.
BRAKE SWITCH INPUT
Circuit K29 provides the brake switch input to the
PCM. Circuit K29 connects to cavity 29 of the PCM.
POWER (DEVICE) GROUND
Circuit Z12 connects to cavities 11 and 12 of the
PCM. The Z12 circuit provides ground for PCM inter-
nal drivers that operate high current devices like the
injectors and ignition coil.
Internal to the PCM, the power (device) ground cir-
cuit connects to the PCM sensor return circuit (from
circuit K4).
HELPFUL INFORMATION
²The grounding point for circuit Z12 is the right
rear of the engine.
²If the system loses ground for the Z12 circuits at
the rear of the engine, the vehicle will not operate.
Check the connection at the ganged-ground circuit
eyelet.
DIAGRAM INDEX
Component Page
Automatic Shut Down Relay.................8W-30-6
Camshaft Position Sensor...................8W-30-8
Crankshaft Position Sensor..................8W-30-9
Data Link Connector......................8W-30-11
Distributor Ignition Coil....................8W-30-11
Engine Coolant Temperature Sensor.............8W-30-9
Fuel Injector #1.........................8W-30-7
Fuel Injector #2.........................8W-30-7
Fuel Injector #3.........................8W-30-7
Fuel Injector #4.........................8W-30-7
Fuel Injector #5.........................8W-30-7
Fuel Injector #6.........................8W-30-7
Fuel Pump Relay........................8W-30-12
Fuel Tank Gauge Level Sending Unit...........8W-30-12
Fuse 2 (PDC)...........................8W-30-6
Fuse 6 (PDC)...........................8W-30-6
Fuse 11 (PDC).......................8W-30-6, 11
Fuse 14 (PDC)..........................8W-30-6
Heated Oxygen Sensor....................8W-30-10
Idle Air Control Motor.....................8W-30-10
Ignition Switch.......................8W-30-6, 12
Instrument Cluster....................8W-30-11, 12
Intake Air Temperature Sensor................8W-30-9
MAP Sensor............................8W-30-8
Powertrain Control Module.............8W-30-6 thru 12
Throttle Position Sensor....................8W-30-8
Vehicle Speed Sensor.....................8W-30-11
J8W-30 FUEL/IGNITIONÐXJ-RHD 8W - 30 - 5

DIAGRAM INDEX
Component Page
4WD Switch.........................8W-40-9, 13
4WD Indicator Lamp....................8W-40-9, 13
ABS Control Module...................8W-40-10, 13
Brake Warning Switch...................8W-40-9, 14
Chime/Buzzer Module...................8W-40-8, 12
Dimming Module........................8W-40-11
Diode...............................8W-40-13
Engine Coolant Temperature Sending Unit.........8W-40-6
Engine Oil Pressure Sending Unit..............8W-40-6
Fuse 5 (PDC)........................8W-40-4, 11
Fuse 6 (PDC)......................8W-40-4, 8, 12
Fuse 11 (PDC).......................8W-40-8, 12
Fuse 9 (Fuse Block)....................8W-40-4, 11
Fuse 25 (Fuse Block)...................8W-40-4, 11Component Page
Fuse 26 (Fuse Block).................8W-40-4, 8, 12
Fog Lamp Switch Lamp...................8W-40-11
Headlamp Switch......................8W-40-4, 11
Headlamp Delay Module.................8W-40-8, 12
Headlamp Dimmer Switch...................8W-40-5
Ignition Switch.................8W-40-4, 6, 8, 12, 14
Instrument Cluster................8W-40-4 thru 7, 14
Low Washer Fluid Lamp Switch............8W-40-8, 12
Overhead Console.....................8W-40-8, 12
Park Brake Switch.....................8W-40-9, 14
Powertrain Control Module..............8W-40-6, 9, 14
Telltale Connector (Instrument Cluster).....8W-40-8 thru 14
J8W-40 INSTRUMENT CLUSTERÐXJ-RHD 8W - 40 - 3

SPLICE LOCATIONS
GENERAL INFORMATION
This section provides illustrations identifying the
general location of the splices in this vehicle. A spliceindex is provided. Use the wiring diagrams in each
section for splice number identification. Refer to the
index for the proper splice number.
SPLICE LOCATIONS
Splice
NumberLocations Fig.
S101......InT/OforHorn and Radiator Fan Motor....2
S102......Before T/O for A/C Low Pressure Switch....2
S103......Before T/O for A/C Low Pressure Switch....2
S104......After T/O for A/C Low Pressure Switch.....2
S105......After T/O for A/C Low Pressure Switch.....2
S106......Before T/O for MAP Sensor............2
S107......Before T/O for MAP Sensor............2
S108......Before T/O for Injector No. 4...........4
S109......Before T/O for Injector No. 6...........4
S110......After T/O for MAP Sensor.............2
S111......After T/O for MAP Sensor.............2
S112......After T/O for Injectors................3
S113......After T/O for Injectors................3
S114......Before T/O for Brake Warning Switch......3
S115......Before T/O for Brake Warning Switch......3
S116......Before T/O for Brake Warning Switch......3
S117......InT/OforDash Connectors, Before Grommet .3
S118......InT/OforDash Connectors, Before Grommet .3
S119......InT/OforABSControl Module, After Grommet .5
S120......After T/O for Underhood Lamp..........3
S121......Before T/O for PDC..................3
S122......Before T/O for PDC..................3
S123......Before T/O for Ambient Air Temperature
Sensor........................3
S124......Near T/O for Ignition Coil and Generator....4
S125......After T/O for Left Fog Lamp............1
S126......Near Clip for Middle of Gille Opening......1
S127......Before T/O for Right Fog Lamp..........1
S201......Before T/O for Right Door Speaker (With ABS) .6
S201......Before T/O for Right Door Speaker (Without ABS)
...............................6
S202......Before T/O for Right Door Speaker (With ABS) .6
S202......Before T/O for Right Door Speaker
(Without ABS)....................6
S203......After T/O for Right Door Jamb Switch (With
ABS)...........................6
S204......Before T/O for Stop Lamp Switch (With ABS) .6
S205......Before T/O for Stop Lamp Switch (With ABS) .6
S205......Before T/O for Stop Lamp Switch (Without ABS)
...............................6
S206......Before T/O for Stop Lamp Switch (With ABS) .6
S206......After T/O for Heated Rear Window Switch and
Fog Lamp Switch (Without ABS).........6
S207......Before T/O for Headlamp Switch (With ABS) .6
S208......InT/OforHeated Rear Window Switch and Fog
Lamp Switch (With ABS)..............6Splice
NumberLocations Fig.
S208......Before T/O for Headlamp Switch
(Without ABS)....................6
S209......After T/O for Heated Rear Window Switch
and Fog Lamp Switch (With ABS).......6
S209......After T/O for Right Door Jamb Switch
(Without ABS)....................6
S210......After T/O for Heated Rear Window Switch and
Fog Lamp Switch (With ABS)...........6
S210......Before T/O for Headlamp Switch
(Without ABS)....................6
S211......After T/O for Antenna (With ABS)........6
S211......After T/O for A/C-Heater Mode Switch
(Without ABS)....................6
S212......InT/OforRelay Center (With ABS).......6
S212......InT/OforRelay Center (Without ABS).....6
S213......InT/OforRelay Center (With ABS).......6
S214......After T/O for Wiper Switch (With ABS).....6
S214......After T/O for A/C-Heater Mode Switch
(Without ABS)...................6
S215......After T/O for A/C-Heater Blower Motor
Switch (With ABS).................6
S216......After T/O for A/C-Heater Mode Switch
(With ABS)......................6
S216......After T/O for A/C-Heater Blower Motor
Switch (Without ABS)...............6
S217......After T/O for A/C-Heater Mode Switch
(With ABS)......................6
S217......After T/O for A/C-Heater Mode Switch
(Without ABS)....................6
S218......After T/O for A/C-Heater Mode Switch
(With ABS).....................6
S218......InT/OforRelay Center (Without ABS).....6
S219......After T/O for Glove Box (With ABS).......6
S220......After T/O for A/C-Heater Mode Switch
(With ABS)......................6
S220......After T/O for A/C-Heater Mode Switch
(Without ABS)....................6
S221......After T/O for Blower Motor Resistor Block
(With ABS)......................6
S222......Before T/O for Stop Lamp Switch
(Without ABS)....................6
S223......After T/O for Heated Rear Window Switch
and Fog Lamp Switch (Without ABS).....6
S224......After T/O for Glove Box (Without ABS).....6
S301......Bottom of Left Front Door Opening.......9
S302......Bottom of Left Front Door Opening.......9
S303......Bottom of Left Front Door Opening.......9
S304......Bottom of Left Front Door Opening.......9
J8W-95 SPLICE LOCATIONSÐXJ-RHD 8W - 95 - 1

FUEL/IGNITION
INDEX
page page
Automatic Shut Down (ASD) Relay............. 1
Battery Feed.............................. 2
Brake Switch Input......................... 5
Camshaft Position Sensor.................... 3
Crankshaft Position Sensor................... 3
Data Link Connector........................ 5
Diagram Index............................ 5
Engine Coolant Temperature Sensor............ 3
Fuel Injectors............................. 2
Fuel Pump Module......................... 2
Fuel Pump Relay.......................... 2
Heated Oxygen Sensor...................... 3Idle Air Control (IAC) Motor................... 2
Ignition Coil.............................. 2
Ignition Switch............................ 1
Intake Air Temperature Sensor................ 4
Malfunction Indicator Lamp (MIL)............... 5
Manifold Absolute Pressure Sensor............. 4
Park/Neutral Position Switch.................. 4
Power (Device) Ground...................... 5
Power Steering Pressure Switch............... 4
Tachometer Signal......................... 5
Throttle Position Sensor..................... 4
Vehicle Speed Sensor....................... 3
IGNITION SWITCH
Circuit A1 from fuse 4 in the Power Distribution
Center (PDC), supplies battery voltage to the ignition
switch. Depending upon position, the ignition switch
powers circuits A21, A22, A31, and A41.
START POSITION
In the START position, the ignition switch connects
circuit A1 to circuit A41. Circuit A41 connects to the
coil side of the starter motor relay.
Also in the START position, the case grounded ig-
nition switch provides ground for the brake lamp
switch and parking brake lamp switch on circuit G11.
START OR RUN POSITION
In the START and RUN position, the ignition
switch connects circuit A1 with circuit A21. The A21
circuit connects to fuses 5 and 9 in the fuse block.
Fuse 9 powers circuit G5. Fuse 5 powers circuit G50.
²Circuit G5 powers the buzzer module. Circuit G5
also splices to power the daytime running lamps
module (Canada only), A/C compressor clutch relay,
heated rear window relay, and the gauges and indi-
cator lamps in the instrument cluster.
RUN (ONLY) POSITION
When the ignition switch is in the RUN position, it
connects circuit A1 to circuit A22. Circuit A22 powers
fuses 1, 12, and 13 in the fuse block.
²Fuse 1 powers the rear wiper system on circuit
V23.
²Fuse 12 feeds the blower motor and air condition-
ing system on circuit C1.
²Fuse 13 feeds circuit F15 which powers the ABS
module and connects to the coil side of the ABS
power relay.
ACCESSORY OR RUN POSITION
In the ACCESSORY or RUN position, the ignition
switch connects circuit A1 to circuit A31. Circuit A31
connects to a bus bar in the fuse block that feeds
fuses 4 and 7 along with the circuit breaker in cavity
11 .
²Fuse 4 powers circuit L5 which feeds the turn sig-
nal flasher.
²Fuse 7 powers circuit F30. Circuit F30 supplies
power to the radio, radio relay, and the cigar lighter.
²The circuit breaker in cavity 11 powers the V6 cir-
cuits which feed the wiper switch and wiper motor.
AUTOMATIC SHUT DOWN (ASD) RELAY
When the ignition switch is in either the START or
RUN position, it connects circuit A1 from fuse 4 in
the Power Distribution Center (PDC) to circuit A21.
Circuit A21 powers fuse 5 in the fuse block. Circuit
G50 from fuse 5 splices to power the coil side of the
Automatic Shut Down (ASD) relay. The Powertrain
Control Module (PCM) provides ground for the relay
on circuit K51. Circuit K51 connects to cavity 51 of
the PCM.
When the PCM grounds the ASD relay, contacts in-
side the relay close and connect circuit A14 from fuse
1 in the PDC to circuit A142. Circuit A142 splices to
the generator field terminal, fuel injectors, ignition
coil, and heated oxygen sensor. Circuit A142 also con-
nects to cavity 57 of the PCM.
Circuit A14 from fuse 1 in the PDC supplies bat-
tery voltage to the contact side of the ASD relay.
HELPFUL INFORMATION
²Along with supplying voltage to the ASD relay
contacts, circuit A14 supplies voltage to the contact
side of the fuel pump relay.
²Circuit G50 also supplies battery voltage to the
coil side of the fuel pump relay.
²Circuit A14 also connects to cavity 3 of the PCM.
J8W-30 FUEL/IGNITIONÐYJ VEHICLES 8W - 30 - 1

²Circuit K60 connects to cavity 60 of the PCM.
VEHICLE SPEED SENSOR
Circuit K7 supplies 8 volts from the Powertrain
Control Module (PCM) to the vehicle speed sensor.
The K7 circuit connects to cavity 7 of the PCM.
Circuit G7 from the vehicle speed sensor provides
an input signal to the PCM. The G7 circuit connects
to cavity 47 of the PCM.
The PCM provides a ground for the vehicle speed
sensor signal (circuit G7) through circuit K4. Circuit
K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
²Circuit G7 splices to the speedometer, and Day-
time Running Lamp module (DRL).
²Circuit K7 splices to supply 8 volts to the camshaft
position sensor and crankshaft position sensor.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Intake air temperature sensor
HEATED OXYGEN SENSOR
When the Automatic Shut Down (ASD) relay con-
tacts close, they connect circuits A14 and A142. Cir-
cuit A142 splices to supply voltage to the heated
oxygen sensor.
Circuit K41 delivers the signal from the heated ox-
ygen sensor to the Powertrain Control Module
(PCM). Circuit K41 connects to cavity 41 of the PCM.
The PCM provides a ground for the heated oxygen
sensor signal (circuit K41) through circuit K4. Circuit
K4 connects to cavity 4 of the PCM connector.
Circuit Z1 provides a ground for the heater circuit
in the sensor. Circuit Z1 terminates at the rear of the
engine.
HELPFUL INFORMATION
²Along with supplying voltage to the ASD relay
contacts, circuit A14 supplies voltage to the contact
side of the fuel pump relay.
²Circuit A142 splices to supply voltage to the fuel
injectors, ignition coil, and heated oxygen sensor.
Circuit K4 splices to supply ground for the signals
from the following:
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
CAMSHAFT POSITION SENSOR
The Powertrain Control Module (PCM) supplies 8
volts to the camshaft position sensor (in distributor)
on circuit K7. Circuit K7 connects to cavity 7 of the
PCM.
The PCM receives the camshaft position sensor sig-
nal on circuit K44. Circuit K44 connects to cavity 44
of the PCM.
The PCM provides a ground for the camshaft posi-
tion sensor signal (circuit K44) through circuit K4.
Circuit K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
²Circuit K7 splices to supply 8 volts to the crank-
shaft position sensor and the vehicle speed sensor.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
CRANKSHAFT POSITION SENSOR
The Powertrain Control Module (PCM) supplies 8
volts to the crankshaft position sensor on circuit K7.
Circuit K7 connects to cavity 7 of the PCM.
The PCM receives the crankshaft position sensor
signal on circuit K24. Circuit K24 connects to cavity
24 of the PCM.
The PCM provides a ground for the crankshaft po-
sition sensor (circuit K24) through circuit K4. Circuit
K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
²Circuit K7 splices to supply 8 volts to the crank-
shaft position sensor and the vehicle speed sensor.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
ENGINE COOLANT TEMPERATURE SENSOR
The engine coolant temperature sensor provides an
input to the Powertrain Control Module (PCM) on
circuit K2. From circuit K2, the engine coolant tem-
perature sensor draws up to 5 volts from the PCM.
The sensor is a variable resistor. As coolant temper-
ature changes, the resistance in the sensor changes,
causing a change in current draw. The K2 circuit
connects to cavity 2 of the PCM.
J8W-30 FUEL/IGNITIONÐYJ VEHICLES 8W - 30 - 3

The PCM provides a ground for the engine coolant
temperature sensor signal (circuit K2) through circuit
K4. Circuit K4 connects to cavity 4 of the PCM con-
nector.
HELPFUL INFORMATION
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Vehicle speed sensor
THROTTLE POSITION SENSOR
From the Powertrain Control Module (PCM), cir-
cuit K6 supplies 5 volts to the Throttle Position Sen-
sor (TPS). Circuit K6 connects to cavity 6 of the
PCM.
Circuit K22 delivers the TPS signal to the PCM.
Circuit K22 connects to cavity 22 of the PCM.
The PCM provides a ground for the throttle posi-
tion sensor signal (circuit K22) through circuit K4.
Circuit K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
Refer to Group 14 for throttle position sensor oper-
ation.
Circuit K6 splices to supply 5 volts to the Manifold
Absolute Pressure (MAP) sensor.
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
From the Powertrain Control Module (PCM), cir-
cuit K6 supplies 5 volts to the Manifold Absolute
Pressure (MAP) sensor. Circuit K6 connects to cavity
6 of the PCM.
Circuit K1 delivers the MAP signal to the PCM.
Circuit K1 connects to cavity 1 of the PCM.
The PCM provides a ground for the MAP sensor
signal (circuit K1) through circuit K4. Circuit K4 con-
nects to cavity 4 of the PCM.
HELPFUL INFORMATION
Refer to Group 14 for MAP sensor operation.
Circuit K6 splices to supply 5 volts to the throttle
position sensor.Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Intake air temperature sensor
²Throttle position sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
INTAKE AIR TEMPERATURE SENSOR
The intake air temperature sensor provides an in-
put to the Powertrain Control Module (PCM) on cir-
cuit K21. Circuit K21 connects to cavity 21 of the
PCM.
From circuit K21, the intake air temperature sen-
sor draws voltage from the PCM. The sensor is a
variable resistor. As intake air temperature changes,
the resistance in the sensor changes, causing a
change in current draw.
The PCM provides a ground for the intake air tem-
perature sensor signal (circuit K21) through circuit
K4. Circuit K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
Circuit K4 splices to supply ground for the signals
from the following:
²Heated oxygen sensor
²Camshaft position sensor
²Crankshaft position sensor
²Throttle position sensor
²Manifold absolute pressure sensor
²Engine coolant temperature sensor
²Vehicle speed sensor
PARK/NEUTRAL POSITION SWITCH
When closed, the case-grounded park/neutral posi-
tion switch provides a ground path on circuit T41 for
the coil side of the starter motor relay. Circuit A41
from the ignition switch provides battery voltage to
the coil side of the relay.
Circuit T41 splices to cavity 30 of the Powertrain
Control Module (PCM). The park/neutral position
switch provides an input to the (PCM).
HELPFUL INFORMATION
²In the START position, the ignition switch con-
nects circuit A1 from the Power Distribution Center
(PDC) to circuit A41. Fuse 4 in the fuse block pro-
tects circuits A1 and A41.
²The Park/Neutral position switch and back-up
lamp switch are molded together.
POWER STEERING PRESSURE SWITCH
The Powertrain Control Module (PCM) supplies
voltage to the power steering pressure switch on cir-
cuit K10. Circuit Z1 provides ground for the switch.
When the switch closes, voltage flows through the
8W - 30 - 4 8W-30 FUEL/IGNITIONÐYJ VEHICLESJ

switch to ground on circuit Z1. The switch closes dur-
ing periods of high power steering pump load and
low engine speed; such as parking maneuvers. Cir-
cuit K10 connects to cavity 10 of the PCM.
TACHOMETER SIGNAL
The Powertrain Control Module (PCM) supplies the
signal for the tachometer on circuit G21. Circuit G21
connects to cavity 43 of the PCM.
MALFUNCTION INDICATOR LAMP (MIL)
The Powertrain Control Module (PCM) provides
ground for the instrument cluster malfunction indica-
tor lamp on circuit G3. The MIL displays the mes-
sage CHECK ENGINE when illuminated. Circuit G5
provides voltage for the lamp.
DATA LINK CONNECTOR
Circuit G50 supplies battery voltage to the data
link connector. Circuit G50 originates at fuse 5 in the
fuse block. Circuit G50 is double crimped at the data
link connector and connects to cavity 9 of the Power-
train Control Module (PCM).
Circuit A21 from the ignition switch powers fuse 5
when the switch is in the START or RUN positions.
In the START or RUN position the ignition switch
connects circuit A1 from fuse 4 in the Power Distri-
bution Center (PDC) with circuit A21.
Circuit D20 connects to cavity 45 of the PCM. Cir-
cuit D20 is the SCI receive circuit for the PCM.
Circuit D21 connects to cavity 25 of the PCM. Cir-
cuit D21 is the SCI transmit circuit for the PCM.
Circuit Z11 provides ground for the data link con-
nector. Circuit Z11 splices to circuit Z1 which termi-
nates at the right rear of the engine. Circuit Z11 also
connects to cavity 5 of the PCM.
HELPFUL INFORMATION
²Circuit Z1 also supplies a ground for the PCM
high current drivers.
²If the system loses ground for the Z1 and Z11 cir-
cuits at the right rear of the engine, the vehicle will
not operate. Check the connection at the ganged-
ground circuit eyelet.
BRAKE SWITCH INPUT
Circuit V40 provides the brake switch input to the
Powertrain Control Module (PCM). Circuit V40 con-
nects to cavity 29 of the PCM.
POWER (DEVICE) GROUND
Circuit Z11 connects to cavities 11 and 12 of the
Powertrain Control Module (PCM). The Z1 circuit
provides ground for PCM internal drivers that oper-
ate high current devices like the injectors and igni-
tion coil.
Internal to the PCM, the power (device) ground cir-
cuit connects to the PCM sensor return circuit (from
circuit K4).
HELPFUL INFORMATION
²The grounding point for circuit Z1 is the right rear
of the engine.
²If the system loses ground for the Z1 circuits at
the rear of the engine, the vehicle will not operate.
Check the connection at the ganged-ground circuit
eyelet.
DIAGRAM INDEX
Component Page
Automatic Shut Down Relay...............8W-30-6, 14
Camshaft Position Sensor................8W-30-10, 16
Crankshaft Position Sensor...............8W-30-10, 16
Data Link Connector...................8W-30-11, 17
Daytime Running Lamps (DRL) Module.......8W-30-11, 17
Engine Coolant Temperature Sensor..........8W-30-9, 18
Fuel Pump Relay........................8W-30-20
Fuel Tank Level Unit......................8W-30-21
Fuse 1 (PDC)........................8W-30-6, 14
Fuse 4 (PDC)........................8W-30-6, 14
Fuse 5 (Fuse Block).................8W-30-6, 14, 20
Heated Oxygen Sensor..................8W-30-7, 15
Idle Air Control Motor..................8W-30-12, 18
Ignition Switch.....................8W-30-6, 14, 20
Ignition Coil........................8W-30-12, 18
Injectors (4.0L).........................8W-30-13
Injectors (2.5L)..........................8W-30-8
Instrument Cluster....................8W-30-11, 17
Intake Air Temperature Sensor.............8W-30-9, 18
MAP Sensor.........................8W-30-9, 18
Power Steering Pressure Switch..............8W-30-12
Powertrain Control Module.............8W-30-6 thru 21
Throttle Position Sensor.................8W-30-9, 18
Vehicle Speed Sensor..................8W-30-11, 17
J8W-30 FUEL/IGNITIONÐYJ VEHICLES 8W - 30 - 5

INSTRUMENT CLUSTER
INSTRUMENT CLUSTER
The instrument cluster contains the gauges and
warning lamps. All gauges have magnetic move-
ments.
When the ignition switch is in either the START or
RUN position, circuit A1 from fuse 4 in the Power
Distribution Center (PDC) connects to circuit A21.
Circuit A21 powers fuse 9 in the fuse block. Fuse 9
powers circuit G5. One branch of circuit G5 connects
directly to the combination buzzer. The other branch
of circuit G5 splices to power the gauges, speedome-
ter, tachometer, voltmeter, indicator lamps, and
warning lamps in the instrument cluster.
When the parking lamps or headlamps are ON, the
headlamp switch connects circuit F33 to circuit L7.
Circuit L7 splices to the dimmer switch. Circuit E1
from the dimmer switch powers fuse 10 in the fuse
block when the parking lamps or headlamps are ON.
Circuit E2 from fuse 10 in the fuse block feeds the
illumination lamps in the instrument cluster.
Circuit Z1 provides ground the instrument cluster
illumination lamps, gauges and warning lamps.
HELPFUL INFORMATION
²Circuit G5 also powers the heated rear window,
A/C compressor clutch relay. On Canadian vehicles,
circuit G5 powers the Daytime Running Lamps
(DRL) module.
²Circuit F33 originates at fuse 8 in the fuse block.
Circuit A6 from fuse 3 in the PDC powers fuse 8 in
the fuse block.
ENGINE COOLANT TEMPERATURE GAUGE
Circuit G20 connects the engine coolant tempera-
ture gauge to the engine coolant temperature sensor.
The sensor is a variable resistor and case grounded
to the engine. Circuit G5 connects to the instrument
cluster and supplies voltage for the gauge.
The gauge uses two coils. The first coil has fixed
current flowing through it to maintain magnetic field
strength. Circuit Z1 provides ground for the fixed
current coil. The current level passing through the
second coil is controlled by the variable resistor in
the engine coolant temperature sender. The changing
current varies the magnetic field in the second coil.
Refer to group 8E, Instrument Panel and Gauges
for gauge operation.
FUEL GAUGE
Circuit G4 connects the fuel level sensor to the fuel
gauge in the instrument cluster. Circuit G5 supplies
voltage to the fuel gauge. The fuel level sensor draws
voltage from circuit G5 through the fuel gauge on cir-
cuit G4.The gauge uses two coils. The first coil has fixed
current flowing through it to maintain magnetic field
strength. Circuit Z1 provides ground for the fixed
current coil. The current level passing through the
second coil is controlled by the variable resistor in
the fuel level sensor. The changing current varies the
magnetic field in the second coil.
Circuit Z2 provides the ground path for the fuel
level sensor.
Refer to group 8E, Instrument Panel and Gauges
for gauge operation.
OIL PRESSURE GAUGE
The case grounded oil pressure sending unit is a
variable resistor. The sending unit connects to the oil
pressure gauge on circuit G60.
Circuit G5 connects to the instrument cluster and
supplies battery voltage to the oil pressure gauge.
The gauge uses two coils. The first coil has fixed cur-
rent flowing through it to maintain magnetic field
strength. Circuit Z1 provides ground for the fixed
current coil. The current level passing through the
second coil is controlled by the variable resistor in
the oil pressure sending unit. The changing current
varies the magnetic field in the second coil.
Refer to group 8E, Instrument Panel and Gauges
for gauge operation.
TACHOMETER
The Powertrain Control Module (PCM) provides
the tachometer signal to the electronic tachometer on
circuit G21. Circuit G21 originates at cavity 43 of the
PCM. Circuit Z1 provides ground for the tachometer's
internal logic circuits.
SPEEDOMETER
The electronic speedometer and odometer receive a
signal from the vehicle speed sensor on circuit G7.
Circuit G5 connects to the instrument cluster and
supplies battery voltage to the speedometer. Circuit
Z1 provides ground for the speedometer internal logic
circuits.
Circuit G7 splices to connect to the Powertrain
Control Module (PCM) and if equipped, the Daytime
Running Lamps (DRL) module.
FOUR-WHEEL DRIVE (4WD) INDICATOR LAMP
When the 4WD switch closes, circuit Z1 provides
ground for the 4WD indicator lamp in the instrument
panel. Circuit G5 connects to the instrument cluster
and supplies battery voltage to the 4WD indicator
lamp. Circuit G1 connects the indicator lamp to the
4WD switch.
J8W-40 INSTRUMENT CLUSTERÐYJ VEHICLES 8W - 40 - 1

MALFUNCTION INDICATOR (CHECK ENGINE)
LAMP
The Powertrain Control Module (PCM) provides
ground for the malfunction indicator (Check Engine)
lamp on circuit G3. Circuit G3 connects to cavity 32
of the PCM. Circuit G5 connects to the instrument
cluster and supplies battery voltage for the malfunc-
tion indicator lamp. When illuminated, the malfunc-
tion indicator lamp displays the message CHECK
ENGINE.
For information regarding diagnostic trouble code
access using the malfunction indicator lamp, refer to
Group 14, Fuel Systems.
UP-SHIFT LAMP
On vehicles equipped with a manual transmission,
the Powertrain Control Module (PCM) provides
ground for the Up-Shift lamp on circuit K54. Circuit
G5 provides battery voltage for the lamp.
ABS WARNING LAMP
Circuit G5 provides power for the ABS warning
lamp at the instrument cluster. Ground for the ABS
warning lamp is provided by either the ABS control
module or by the ABS power relay when the relay is
not energized. The ABS control module illuminates
the lamp by providing ground on circuit G19.
Circuit G19 splices to connect to circuit B15
through a diode. When the ABS power relay is not
energized, it connects circuit B15 to circuit Z12. The
ground path for the warning lamp is provided
through the diode to circuit B15, through the ABS
power relay to ground on circuit Z12.
The diode between circuit G19 and B15 prevents
voltage from flowing to the ABS control module when
the ABS power relay switches to supply power on cir-
cuit B15.
BRAKE WARNING LAMP
Circuit G5 provides battery voltage for the brake
warning lamp. Circuit G11 can provide ground for
the lamp in 3 ways. The first ground path is through
the ignition switch when the key is in the START po-
sition.
The second ground path for the brake warning
lamp on circuit G11 is through the case grounded
brake warning switch. When the switch closes it pro-
vides a ground.
The third ground path on circuit G11 is through
the case grounded park brake switch. When the
switch closes it provides ground.
HIGH BEAM INDICATOR LAMP
Circuit G34 supplies power for the high-beam indi-
cator lamp when the operator either flashes the opti-
cal horn (high beams) or selects high beam operation.
Circuit Z1 provides the ground path for the lamp.
Circuit L3 from the headlamp switch powers the
high beam circuits of the headlamps. On vehicles not
equipped with Daytime Running Lamps (DRL), cir-
cuit G34 double crimps to circuit L3 at the bulkhead
connector.
On vehicles equipped with DRL, circuit L3 splices
to the DRL module. The DRL module powers circuit
G34.
TURN SIGNAL INDICATOR LAMPS
Circuit L61 supplies battery voltage to the left turn
signal indicator lamp. The right turn signal indicator
lamp receives battery voltage from circuit L60. The
turn signal/hazard flasher switch powers circuits L60
and L61. Circuit Z1 provides ground for the lamps.
HELPFUL INFORMATION
²If the warning lamps, gauges and indicator lamps
don't operate, check fuse 4 in the PDC and fuse 9 in
the fuse block.
²If the illumination lamps don't operate, check fuse
10 in the fuse block.
DIAGRAM INDEX
Component Page
4WD Switch............................8W-40-9
ABS Control Module......................8W-40-5
Brake Warning Switch.....................8W-40-5
Combination Buzzer.....................8W-40-7, 8
Daytime Running Lamp (DRL) Module.........8W-40-4, 6
Engine Coolant Temperature Sensor...........8W-40-7, 8
Engine Oil Pressure Sensor..................8W-40-9
Fuse 3 (PDC).......................8W-40-3, 7, 8
Fuse 4 (PDC).......................8W-40-4, 7, 8
Fuse 7 (PDC)...........................8W-40-6
Fuse 8 (Fuse Block)...................8W-40-3, 7, 8
Fuse 9 (Fuse Block).......................8W-40-8
Fuse 10 (Fuse Block).................8W-40-3, 7, 10
Gauge Package......................8W-40-7, 8, 9
Headlamp Switch...................8W-40-3, 6, 7, 8
Headlamp Dimmer Switch...................8W-40-6
Ignition Switch......................8W-40-4, 5, 8
Instrument Cluster...................8W-40-3 thru 9
Panel Lamp Dimmer Switch..............8W-40-3, 7, 8
Park Brake Switch........................8W-40-5
Powertrain Control Module.................8W-40-4, 5
8W - 40 - 2 8W-40 INSTRUMENT CLUSTERÐYJ VEHICLESJ