1995 JEEP CHEROKEE wiring diagram

TRAILER TOW
TRAILER TOW
The factory installed trailer tow system in this ve-
hicle uses three relays and a circuit breaker along
with the trailer tow wiring connector located below
the rear bumper.
Battery voltage for the trailer tow circuit breaker
and relays is supplied on circuit A11. This circuit is
HOT at all times and connects to the power accessory
tap in the fuse block. An in line 10 amp circuit pro-
tected breaker protects circuit A11 and the trailer
tow circuits. The trailer tow circuit breaker is located
in the left rear quarter panel.
STOP LAMP RELAY
Power for the coil side of the stop lamp relay is
supplied by circuit L50. This circuit connects to the
stop lamps. Ground for the coil side is supplied on
circuit Z1.
When the operator depresses the brake pedal, volt-
age flows through the coil of the relay to ground
causing the contacts in the relay to close connecting
circuits A11 and 95.
Circuit 95 connects to the left and right turn signal
relays. Voltage flows through the closed contacts in
the relays to the trailer tow connector.
RIGHT TURN RELAY
Power for the coil side of the right turn relay is
supplied by circuit L60. This circuit connects to the
right side turn signal lamps. Ground for the coil side
of the relay is supplied on circuit Z1.
When the operator turns the right turn signal ON,
power flows through the coil in the relay to ground
causing the contacts in the relay to switch from there
normally CLOSED position to connect circuits 94 and
L60.
Circuit 94 is the feed for the contact side of the re-
lay. Circuit L60 connects from the relay to the trailer
tow connector.
Circuit 94 is fed power through the normally
CLOSED side of the stop lamp relay and circuit A11.
The A11 circuit is HOT at all times and protected by
a 10 amp circuit breaker located in the left rear
quarter panel.
LEFT TURN RELAY
Power for the coil side of the left turn relay is sup-
plied by circuit L61. This circuit connects to the left
side turn signal lamps. Ground for the coil side of the
relay is supplied on circuit Z1.
When the operator turns the left turn signal ON,
power flows through the coil in the relay to ground
causing the contacts in the relay to switch from there
normally CLOSED position to connect circuits 94 and
L61.
Circuit 94 is the feed for the contact side of the re-
lay. Circuit L61 connects from the relay to the trailer
tow connector.
Circuit 94 is fed power through the normally
CLOSED side of the stop lamp relay and circuit A11.
The A11 circuit is HOT at all times and protected by
a 10 amp circuit breaker located in the right rear
quarter panel.
HELPFUL INFORMATION
²Check the In-Line circuit breaker
DIAGRAM INDEX
Component Page
Circuit Breaker (In-Line)....................8W-54-4
Electric Brake Provision....................8W-54-2
Fuse 1 (Fuse Block).......................8W-54-4
Fuse 3 (PDC)...........................8W-54-4
Left Turn Signal Relay.....................8W-54-3
Left Back-Up Lamp.......................8W-54-2
Left Side Marker Lamp.....................8W-54-2
Left Tail/Stop Lamp.......................8W-54-2
Left Turn Signal Lamp.....................8W-54-2
Right Turn Signal Relay....................8W-54-3
Stop Lamp Relay.........................8W-54-3
Trailer Tow Connector......................8W-54-2
J8W-54 TRAILER TOWÐXJ-RHD 8W - 54 - 1

CONNECTOR LOCATIONS
GENERAL INFORMATION
This section provides illustrations identifying com-
ponent and connector locations in the vehicle. A con-nector index is provided. Use the wiring diagrams in
each section for connector number identification. Re-
fer to the index for the proper figure number.
CONNECTOR LOCATIONS
Connector # Color Location Fig.
C101......BK ...Front Left of Engine Compartment . .2
C102......BK ...InFront of Washer Fluid Reservoir . .2
C103......BK ...Bottom of Washer Fluid Reservoir . .2
C104......BK ...Bottom of Washer Fluid Reservoir . .2
C105......BK ...TopofWasher Fluid Reservoir.....2
C106......BK ...TopofRadiator Fan Housing......2
C107......BK ...Left Fender Side Shield.........2
C108......BK ...Left Fender Side Shield.........2
C109......BK ...Near Air Cleaner..............2
C110......BK ...Left Corner of Engine Compartment .2
C111......BK ...Rear of Intake Manifold.........4
C112......BK ...OnThrottle Body.............4
C113......BK ...OnThrottle Body.............4
C114......BK ...Rear of Intake Manifold.........4
C115......GN ...Lower Right of I.P.
C116......BK ...Near ABS Control Module
C117......GN ...Center of Dash Panel...........2
C118......BK ...Injector No. 6...............4
C119......BK ...Injector No. 5...............4
C120......BK ...Injector No. 4...............4
C121......BK ...Injector No. 3...............4
C122......BK ...Injector No. 2...............4
C123......BK ...Injector No. 1...............4
C124......BK ...OnEngine, Behind Power
Steering Pump.............4
C125......BK ...OnThermostat Housing.........4
C126......BK ...OnABSControl Module.........7
C127......BK ...Near ABS Control Module........7
C128......BK ...Near Distributor..............4
C129......BK ...Near Center of Dash Panel.......3
C130......GY ...Near Center of Dash Panel.......3
C131......BK ...Near Left Kick Panel
C132......BK ...OnSteering Column...........6
C133......BK ...Near Center of Dash Panel.......3
C134......BK ...Center of Dash Panel...........3
C135......BK ...Below Brake Master Cylinder......3
C136......BK ...Right Corner of Engine Compartment .3
C137......BK ...Right Side of Hood............3
C138......BK ...Near ABS Control Module
C139......BK ...Near ABS Control Module........7
C140......GY ...Near ABS Control Module........7
C141......GN ...Near ABS Control Module........7
C142......BK ...Right Fender Side Shield........3
C143......BK ...Right Fender Side Shield........3
C144......BK ...Right Fender Side Shield........3
C145......BK ...Right Fender Side Shield........3
C146......BK ...Below Battery................3
C147......BK ...Rear of Battery...............5
C148......BK ...AtStarter Motor..............4
C149......BK ...Right Side of Engine Near Distributor .4
C150......BK ...Rear of Generator.............4
C151......BK ...Rear of Generator.............5Connector # Color Location Fig.
C152......BK ...Behind Lens................1
C153......BK ...Left Rear of Radiator Closure Panel .1
C154......BK ...Behind Lens................1
C155......BK ...Behind Lens................1
C156......BK ...Behind Lens................1
C157......BK ...Center of Grille Opening.........1
C158......BK ...Center of Grille Opening.........1
C159......BK ...Behind Lens................1
C160......BK ...Behind Lens................1
C201......GY ...Center Bottom of I.P............8
C202......WT ...Center Bottom of I.P............8
C203......BK ...Behind Right Kick Panel........12
C204......BK ...Right Side of I.P.
C205......BK ...Left Rear of I.P...............8
C206......BK ...Left Rear of I.P...............8
C207......BK ...Near Right Kick Panel..........7
C208......GN ...Near Right Kick Panel..........7
C209......RD ...Behind Right Kick Panel........12
C210......BK ...Behind Fender Side Shield
C211......BK ...Near Right Kick Panel..........7
C212......BK ...Near Right Kick Panel
C213......BK ...Rear of Headlamp Switch.......10
C214......BK ...Rear of I.P., Right of Steering
Column..................9
C215......BK ...Rear of I.P., Right of Steering
Column..................9
C216......BK ...Rear of I.P., Right of Steering
Column.................9
C217......RD ...Rear of I.P., Right of Steering
Column..................9
C218......BK ...Below Stop Lamp Switch........7
C219......BK ...Rear of I.P., Right of Steering
Column.................9
C220......NAT ..Rear of I.P. Cluster...........10
C221......BK ...Rear of I.P. Cluster...........10
C222......NAT ..Rear of I.P., Left of Steering Column .9
C223......BK ...Rear of I.P., Left of Steering Column .9
C224......BK ...Rear of I.P., Left of Steering Column .9
C225......BK ...Rear of I.P., Left of Steering Column .9
C226......BK ...OnSteering Column...........6
C227......BK ...Near ABS Control Module........7
C228......WT ...Center of I.P.
C229......BK ...Center of I.P.
C230......BK ...OnSteering Column...........6
C231......BK ...OnSteering Column...........6
C232......BK ...OnSteering Column...........6
C233......BK ...Center Bottom of I.P............8
C234......BK ...Rear of I.P., Above Ash Receiver . . .8
C235......BK ...Rear of Radio...............9
C236......BR ...Rear of A/C-Heater Controls.....10
C237......BK ...Center Bottom of I.P............8
C238......BK ...Near ABS Control Module........7
J8W-90 CONNECTOR LOCATIONSÐXJ-RHD 8W - 90 - 1

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

plugged catalytic convertor.
(27) If equipped with automatic transmission, ver-
ify that electrical harness is firmly connected to park/
neutral safety switch. Refer to Automatic
Transmission section of Group 21.
(28) Verify that the harness connector is firmly
connected to the vehicle speed sensor (Fig. 26).
(29) Verify that fuel pump module wire connector
is firmly connected to harness connector.
(30) Inspect fuel hoses at fuel pump module for
cracks or leaks (Fig. 27).
(31) Inspect transmission torque convertor housing
(automatic transmission) or clutch housing (manual
transmission) for damage to timing ring on drive
plate/flywheel.
(32) Verify that battery cable and solenoid feed
wire connections to the starter solenoid are tight andclean. Inspect for chaffed wires or wires rubbing up
against other components (Fig. 28).
POWERTRAIN CONTROL MODULE (PCM) 60-WAY
CONNECTOR
For PCM 60-way connector wiring schematics, refer
to Group 8W, Wiring Diagrams.
Fig. 27 Fuel Pump Module Connector and Fuel HosesÐTypical
Fig. 25 Oxygen Sensor LocationÐTypical
Fig. 26 Vehicle Speed SensorÐTypical
14 - 40 FUEL SYSTEM GENERAL DIAGNOSISJ

PCM SYSTEM SCHEMATICS
Powertrain control system schematics for the 2.5L
4-cylinder and 4.0L 6-cylinder engines are shown in
figures 29, 30, 31 and 32.
These schematics are displayed as a quick refer-
ence only. They are not intended to be all-inclusive.
Refer to the Wiring Diagrams section for detailed in-
formation.
Fig. 28 Starter Solenoid ConnectionsÐTypical
JFUEL SYSTEM GENERAL DIAGNOSIS 14 - 41

EXTENDED IDLE SWITCH TEST
OPTIONAL POLICE PACKAGE ONLY
OPERATION
The extended idle switch is used to raise the en-
gine idle speed to approximately 1000 rpm when the
shifter is in either the Park or Neutral position. A
rocker-type 2-wire switch (extended idle switch) is
mounted to the instrument panel.This switch is
available only with 4.0L engine when supplied
with the optional police package.
TESTING
The extended idle switch will control a ground cir-
cuit going to the powertrain control module (PCM).
When a ground signal (through this switch) has been
received at pin number 10 in the PCM, engine idle
speed will increase.
Bring the engine to normal operating temperature
and turn the extended idle switch to the ON position.
Engine speed should now increase to approximately
1000 rpm when the shifter is in either the Park or
Neutral position. If engine speed does not increase,
apply a good ground to pin number 10 at the PCM
using a small paper clip. Be careful not to damage
the wiring with the paper clip. If the engine speed
now increases, it can be assumed that the PCM is
functioning correctly. Check the instrument panel
mounted switch for a closed ground circuit when in
the ON position. If the engine speed will not increase
after applying a ground to pin number 10, replace
the PCM. Refer to Group 8W, Wiring Diagrams for
circuit and wiring information.
THROTTLE POSITION SENSOR (TPS) TEST
To perform a complete test of the sensor and its cir-
cuitry, refer to DRB scan tool and appropriate Pow-
ertrain Diagnostics Procedures manual. To test the
sensor only, refer to the following:
The throttle position sensor (TPS) can be tested
with a digital voltmeter. The center terminal of the
TPS is the output terminal (Figs. 38 or 39).
With the ignition key in the ON position, back-
probe the TPS connector. Check the TPS output volt-
age at the center terminal wire of the connector.
Check this at idle (throttle plate closed) and at wide
open throttle (WOT). At idle, TPS output voltage
should must be greater than 200 millivolts. At wide
open throttle, TPS output voltage must be less than
4.8 volts. The output voltage should increase gradu-
ally as the throttle plate is slowly opened from idle to
WOT.
TORQUE CONVERTER CLUTCH RELAY TEST
To test the relay only, refer to RelaysÐOperation/
Testing in this section of the group. To test the
torque converter clutch circuit and related compo-nents, refer to the appropriate Powertrain Diagnostic
Procedures manual for operation of the DRB scan
tool.
VEHICLE SPEED SENSOR TEST
To perform a complete test of the sensor and its cir-
cuitry, refer to DRB scan tool and appropriate Pow-
ertrain Diagnostics Procedures manual.
OXYGEN SENSOR (O2S) HEATING ELEMENT TEST
To perform a complete test of the O2S sensor (Fig.
40) and its circuitry, refer to DRB scan tool and ap-
propriate Powertrain Diagnostics Procedures manual.
To test the sensor only, refer to the following:
The oxygen sensor heating element can be tested
with an ohmmeter as follows:
With the sensor at room temperature 25 degrees C
(77 degrees F), disconnect the O2S sensor connector.
Connect the ohmmeter test leads across the white
wire terminals of the sensor connector. Resistance
should be between 5 and 7 ohms. Replace the sensor
if the ohmmeter displays an infinity (open) reading.
Fig. 38 TPS TestingÐ2.5L Engine
Fig. 39 TPS TestingÐ4.0L Engine
14 - 48 FUEL SYSTEM GENERAL DIAGNOSISJ

(8) Disconnect jumper wires from relay and 12 Volt
power source.
If continuity or resistance tests did not pass, re-
place relay. If tests passed, refer to Group 8W, Wiring
Diagrams for additional circuit information. Also re-
fer to the appropriate Powertrain Diagnostic Proce-
dures manual for operation of the DRB scan tool.
STARTER MOTOR RELAY TEST
Refer to Group 8A, Battery/Starting/Charging/Sys-
tem Diagnostics, for starter motor relay testing.
FUEL INJECTOR TEST
To perform a complete test of the fuel injectors and
their circuitry, refer to DRB scan tool and appropri-
ate Powertrain Diagnostics Procedures manual. To
test the injector only, refer to the following:
Disconnect the injector wire connector from the in-
jector. Place an ohmmeter on the injector terminals.
Resistance reading should be approximately 14.5
ohms61.2 ohms at 20ÉC (68ÉF). Proceed to the fol-
lowing Injector Diagnosis chart.When performing
the following tests from the chart, do not leave
electrical current applied to the injector for
longer than five seconds. Damage to injector
coil or internal injector seals could result.
FUEL SYSTEM PRESSURE TEST
Refer to the Fuel Delivery System section of this
group. See Fuel System Pressure Test.
ON-BOARD DIAGNOSTICS (OBD)
The powertrain control module (PCM) has been
programmed to monitor many different circuits of the
fuel injection system. If a problem is sensed in a
monitored circuit often enough to indicate an actual
problem, a Diagnostic Trouble Code (DTC) is stored.
The DTC will be stored in the PCM memory for even-
tual display to the service technician. If the problem
is repaired or ceases to exist, the PCM cancels the
DTC after 51 engine starts.Certain criteria must be met for a diagnostic trou-
ble code (DTC) to be entered into PCM memory. The
criteria may be a specific range of engine rpm, engine
temperature and/or input voltage to the PCM.
It is possible that a DTC for a monitored circuit
may not be entered into memory even though a mal-
function has occurred. This may happen because one
of the DTC criteria for the circuit has not been met.
Example: assume that one of the criteria for the
MAP sensor circuit is that the engine must be oper-
ating between 750 and 2000 rpm to be monitored for
a DTC. If the MAP sensor output circuit shorts to
ground when the engine rpm is above 2400 rpm, a 0
volt input will be seen by the PCM. A DTC will not
be entered into memory because the condition does
not occur within the specified rpm range.
A DTC indicates that the powertrain control mod-
ule (PCM) has recognized an abnormal signal in a
circuit or the system. A DTC may indicate the result
of a failure, but never identify the failed component
directly.
There are several operating conditions that the
PCM does not monitor and set a DTC for. Refer to
the following Monitored Circuits and Non-Monitored
Circuits in this section.
MONITORED CIRCUITS
The powertrain control module (PCM) can detect
certain problems in the fuel injection system.
Open or Shorted Circuit- The PCM can deter-
mine if sensor output (which is the input to PCM) is
within proper range. It also determines if the circuit
is open or shorted.
Output Device Current Flow- The PCM senses
whether the output devices are hooked up.
If there is a problem with the circuit, the PCM
senses whether the circuit is open, shorted to ground
(-), or shorted to (+) voltage.
Oxygen Sensor- The PCM can determine if the
oxygen sensor is switching between rich and lean.
This is, once the system has entered Closed Loop. Re-
fer to Open Loop/Closed Loop Modes Of Operation in
the Component Description/System Operation section
for an explanation of Closed (or Open) Loop opera-
tion.
NON-MONITORED CIRCUITS
The PCM does not monitor the following circuits,
systems or conditions that could have malfunctions
that result in driveability problems. A Diagnostic
Trouble Code (DTC) may not be displayed for these
conditions.
Fuel Pressure:Fuel pressure is controlled by the
vacuum assisted fuel pressure regulator. The PCM
cannot detect a clogged fuel pump inlet filter, clogged
in-line fuel filter, or a pinched fuel supply or return
Fig. 44 Fuel Injector Internal ComponentsÐTypical
JFUEL SYSTEM GENERAL DIAGNOSIS 14 - 51

HEATING AND AIR CONDITIONING TEST PROCEDURES
INDEX
page page
A/C Compressor Clutch..................... 15
A/C Compressor Clutch Relay................ 15
A/C Compressor Clutch Relay................ 16
Air Conditioning ControlsÐXJ Vehicles......... 15
Air Conditioning ControlsÐYJ Vehicles......... 16
Blower Motor............................ 17
Blower Motor Switch....................... 16Compressor Clutch........................ 16
Fin Sensing Cycling Clutch Switch............. 15
Heater Diagnosis......................... 17
Low-Pressure High-Pressure Cut-Off Switch..... 15
Low-Pressure High-Pressure Cut-Off Switch..... 16
Thermostatic Control....................... 16
AIR CONDITIONING CONTROLSÐXJ VEHICLES
The A/C Compressor Clutch is controlled by several
components: the Pressure Cut-Off Switch, Cycling
Clutch Switch, Clutch Relay and Powertrain Control
Module (PCM).
Powertrain Control Module may delay A/C clutch
engagement up to 30 seconds.
Refer to Group 8W Wiring Diagrams for wiring and
terminals. Use volt ohmmeter to test switches.
A/C COMPRESSOR CLUTCH
The clutch assembly consists of a stationary elec-
tromagnetic coil, hub bearing pulley assembly, and
clutch plate. When the coil is energized the plate is
magnetically engaged with the pulley and turns the
compressor shaft.
A/C COMPRESSOR CLUTCH TEST
(1) Unplug clutch coil connector.
(2) Connect a jumper wire from the battery posi-
tive post to the clutch coil terminal. The clutch
should engage, if not leave jumper wire connected
and go to next step.
(3) Connect a jumper wire from clutch coil frame to
chassis ground. The clutch should engage if not re-
pair clutch coil ground or replace coil.
A/C COMPRESSOR CLUTCH RELAY
The A/C compressor clutch relay controls the 12-
volt source to the A/C clutch. The relay is activated
when the PCM receives a A/C request signal from the
fin-sensed cycling clutch switch. The PCM then sends
a ground signal to the relay. The relay is activated
and sends 12-volts to the clutch coil which energizes
the clutch. The relay is located in the power distribu-
tion center.
COMPRESSOR CLUTCH RELAY TEST
For test procedure refer to Powertrain Diagnostic
Service Manual for A/C clutch relay circuit test.
LOW-PRESSURE HIGH-PRESSURE CUT-OFF
SWITCH
The pressure cut-off switch is located on the filter
drier and is wired in series with compressor clutch.
The switch interrupts the power to the compressor
clutch circuit when the pressure drops to 193 kPa (28
psi) or increases above 3100 to 3375 kPa (450 to 490
psi).
PRESSURE CUT-OFF SWITCH TEST
(1) Verify system has correct refrigerant charge.
(2) Turn ignition switch to RUN, A/C blower switch
to ON and control set to MAX.
(3) Unplug pressure cut-off switch and test feed
circuit from select switch. It should be battery volt-
age if not, repair open to select switch.
(4) Test for continuity between the switch termi-
nals. If continuity is not present recover refrigerant
from the system. Replace switch, evacuate and re-
charge system.
FIN SENSING CYCLING CLUTCH SWITCH
The switch is attached to the evaporator coil with
the temperature sensing probe inserted into the coil
fins. This switch prevents condensate water on the
evaporator coil from freezing. It does this by sending
signals to the PCM to cycling the compressor clutch
on and off.
FIN-SENSED CYCLING CLUTCH SWITCH TEST
Test area ambient temperature should be around
21ÉC (70ÉF) for test.
(1) Verify system has correct refrigerant charge.
(2) Start Engine and turn on A/C.
(3) If the compressor clutch cycles ON and OFF 2
to 3 times per minute the cycling clutch switch is
normal. The ambient temperature should be between
20ÉC-30ÉC (68ÉF-90ÉF). Above 32ÉC (90ÉF) the com-
pressor clutch may stay engaged (non cycling) due to
the high heat load, this condition is normal. If the
compressor clutch fails to engage go to next step.
(4) Disconnect wiring harness connector from
switch. With a volt meter test feed circuit from cut-
JHEATING AND AIR CONDITIONING 24 - 15