engine MITSUBISHI MONTERO 1998 Owner's Manual
Page 86 of 1501
ADJUSTMENTS
NOTE: For adjustment procedures, see HEATER SYSTEM article.
TROUBLE SHOOTING
NO COOLING
1) Ensure compressor clutch is operating. If compressor
clutch is operating, go to next step. If compressor clutch is not
operating, check fuses and A/C switch. Check dual-pressure switch.
Check air inlet sensor and air thermosensor. Check A/C compressor
relay. Check A/C compressor clutch coil. Check A/C control unit.
2) Ensure system is properly charged with correct amount of
refrigerant. Evacuate and charge system as necessary. Ensure receiver-
drier is not clogged. Check compressor belt for proper tension. Check
for clogged expansion valve. Check compressor operation. Repair or
replace components as necessary.
INSUFFICIENT AIRFLOW
Check for air leakage at air duct joint. Check for frost on
evaporator. Ensure blower motor is operating properly. Check for
obstructed air intake.
INSUFFICIENT COOLING
Ensure system is properly charged with correct amount of
refrigerant and free of air and moisture. Evacuate and charge system
as necessary. Ensure receiver-drier is not clogged. Ensure sufficient
airflow through condenser exists. Check compressor belt for proper
tension. Check compressor operation. Repair or replace compressor as
necessary. Check for clogged expansion valve. Replace expansion valve
as necessary. Check A/C compressor clutch coil.
INTERMITTENT COOL AIR
Check for air or moisture in system. Evacuate and charge
system as necessary. Check for expansion valve malfunction. Replace
expansion valve if necessary. Check compressor belt for proper
tension.
TESTING
* PLEASE READ THIS FIRST *
WARNING: To avoid injury from accidental air bag deployment, read and
carefully follow all SERVICE PRECAUTIONS and DISABLING &
ACTIVATING AIR BAG SYSTEM procedures in AIR BAG RESTRAINT
SYSTEM article.
NOTE: For testing procedures not covered in this article, see
HEATER SYSTEM article.
A/C SYSTEM PERFORMANCE
1) Park vehicle out of direct sunlight. Install A/C gauge
set. Start engine and allow it to idle at 1000 RPM. Turn A/C on. Set
A/C controls to recirculated air, panel (vent) mode and full cold
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With A/C switch in indicated position, ensure continuity
exists between listed terminals. See appropriate A/C SWITCH CONTINUITY
TEST table. See Fig. 2.
A/C SWITCH CONTINUITY TEST TABLE
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Switch Position Terminal No. Continuity
OFF ...................... ( 1) ...................... No
ECONO ................... 1 & 3 .................... Yes
A/C ................... 1, 3 & 4 ................... Yes
( 1) - Continuity should not exist between any terminals.
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Fig. 2: Identifying A/C Switch Terminals
Courtesy of Mitsubishi Motor Sales of America.
A/C ENGINE COOLANT TEMPERATURE SWITCH
1) Disconnect A/C engine coolant temperature switch
connector. Remove A/C engine coolant temperature switch. Carefully
heat a pan of oil and hold coolant temperature switch up to threads in
oil. Coolant switch is normally closed (continuity exists).
2) When oil reaches 235-243
F (112-118C), coolant switch
should open (no continuity). Replace A/C engine coolant temperature
switch if it does not test as specified. See Fig. 3.
Page 89 of 1501
Fig. 3: Testing A/C Engine Coolant Temperature Switch
Courtesy of Mitsubishi Motor Sales of America.
AIR THERMOSENSOR & AIR INLET SENSOR
1) Disconnect sensor connector at evaporator case. See
Fig. 12 . Using ohmmeter, measure resistance between sensor terminals.
See AIR THERMOSENSOR & AIR INLET SENSOR SPECIFICATIONS table.
2) If resistance is not within specifications, faulty sensor
must be replaced. If resistance is within specifications and all other
components are okay, replace A/C Compressor Control Unit (ACCU).
AIR THERMOSENSOR & AIR INLET SENSOR SPECIFICATIONS TABLE
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Sensor Temperature F (C) Ohms
-20 (-4) .......................................... 12,000
32 (0) .............................................. 4800
50 (10) ............................................. 2800
68 (20) ............................................. 1800
86 (30) ............................................. 1000
104 (40) ............................................. 800
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BLOWER RESISTOR
Disconnect blower resistor connector. Using an ohmmeter,
measure resistance between indicated terminals. See BLOWER RESISTOR
RESISTANCE table. See Fig. 4
BLOWER RESISTOR RESISTANCE TABLE
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Switch Continuity Between
Position Terminal No.
OFF .................................................. (1)
Low ......................................... 1 & 8; 3 & 5
Medium-Low .................................. 1 & 8; 5 & 6
Medium-High .............................. 1, 4 & 8; 2 & 5
High ..................................... 1, 4 & 8; 5 & 7
( 1) - Continuity should not exist between any terminals.
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DUAL-PRESSURE SWITCH
Disconnect dual-pressure connector, and connect a jumper wire
across harness connector terminals. Connect manifold gauge set to
system, and check operating pressures. Dual-pressure switch will allow
compressor operation when system pressure is within specification.
When high or low pressure side of dual-pressure switch is at operation
pressure (ON), condition is normal if there is continuity between the
respective terminals. If continuity is not present when switch is ON,
replace dual-pressure switch. See PRESSURE SWITCH SPECIFICATIONS
table.
PRESSURE SWITCH SPECIFICATIONS TABLE ( 1)
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Application ON Pressure OFF Pressure
psi (kg/cm) psi (kg/cm)
High Pressure ......... 455 (32) .............. 541 (38)
Low Pressure .......... 32 (2.2) .............. 28 (2.0)
( 1) - With ambient temperature at 80
F (27C). \
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COMPRESSOR CLUTCH
Disconnect wiring to compressor clutch. Connect battery
voltage directly to A/C compressor clutch wiring harness terminals. If
click is heard, clutch engagement is okay. If click is not heard,
pulley and armature are not making contact. Repair or replace as
necessary.
RELAYS
4-Terminal Relay
1) Remove relay from relay box located in engine compartment.
Using an ohmmeter, check continuity between relay terminals.
Continuity should exist between terminals No. 2 and 4, but not between
terminals No. 1 and 3. See Fig. 6.
2) Connect battery voltage to terminal No. 2, and ground
terminal No. 4. Ensure continuity now exists between terminals No. 1
and 3. If continuity is not as specified, replace relay.
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A/C SWITCH
Removal & Installation
Lower glove box. Remove instrument cover. Remove lap cooler
and foot shower ducts. Remove center panel and A/C-heater control
panel. Remove bezel and knob. Disconnect A/C switch connector, and
remove A/C switch. To install, reverse removal procedure.
A/C ENGINE COOLANT TEMPERATURE SWITCH
Removal & Installation
Drain coolant below level of thermostat housing. See Fig. 8.
Remove A/C engine coolant temperature switch wiring harness connector,
and unscrew A/C engine coolant temperature switch from thermostat
housing. To install, reverse removal procedure. Tighten A/C engine
coolant temperature switch to specification. See TORQUE SPECIFICATIONS
. Add coolant and check for leaks.
Fig. 8: Locating A/C Engine Coolant Temperature Switch
Courtesy of Mitsubishi Motor Sales of America.
BLOWER MOTOR & RESISTOR
Removal & Installation
Remove right side foot shower duct. Disconnect blower and/or
resistor. Remove blower motor and/or resistor. See Fig. 9. To install,
reverse removal procedure.
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Removal & Installation
1) Discharge A/C system, using approved refrigerant
recovery/recycling equipment. Remove front grille and grille brackets.
Remove hood latch bracket mounting bolt. Remove hood latch brace.
Remove A/T oil cooler and engine oil cooler mounting bolts and
brackets.
2) Remove receiver bracket and receiver. Remove condenser fan
motor. Disconnect pressure lines from condenser. Remove condenser
mounting bolts. Lift condenser from vehicle. To install, reverse
removal procedure. See Fig. 11. If replacing condenser, add 1.4 ounces
of refrigerant oil to new condenser.
Fig. 11: Exploded View Of Condenser & Condenser Fan Motor
Courtesy of Mitsubishi Motor Sales of America.
EVAPORATOR ASSEMBLY
Page 97 of 1501
Removal & Installation
1) Discharge A/C system, using approved refrigerant
recovery/recycling equipment. Remove glove box with lower frame
attached. Loosen duct joint bolt to free duct joint. Disconnect A/C
switch harness. Disconnect evaporator drain hose.
2) Disconnect refrigerant lines at firewall side of engine
compartment. Remove evaporator top bolts in passenger compartment.
Remove evaporator assembly. To install, reverse removal procedure. See
Figs. 12 and 13. If replacing evaporator, add 1.4 ounces of
refrigerant oil to new evaporator.
Fig. 12: Removing Evaporator Assembly
Courtesy of Mitsubishi Motor Sales of America.
Page 99 of 1501
Removal & Installation
Discharge A/C system, using approved refrigerant
recovery/recycling equipment. Disconnect refrigerant temperature
sensor wiring connector. Remove temperature sensor from compressor. To
install, reverse removal procedure. Use new "O" ring on temperature
sensor.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE \
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Application Ft. Lbs. (N.m)
A/C Compressor Bolt/Nut .................... 17-20 (23-27)
A/C Compressor Bracket Bolt/Nut .................. 37 (50)
A/C Compressor Clutch Coil Nut ................... 12 (16)
A/C Engine Coolant Temperature Switch ............ 26 (35)
INCH Lbs. (N.m)
Blower Motor Bolts/Nuts ........................... 44 (5)
Condenser Bolts/Nuts ............................ 106 (12)
Dual-Pressure Switch ............................. 89 (10)
Evaporator Assembly Bolts/Nuts .................... 44 (5)
Heater Assembly Bolts/Nuts ........................ 44 (5)
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WIRING DIAGRAMS
Page 101 of 1501
A/C SYSTEM GENERAL SERVICING
1998 Mitsubishi Montero
1998 AIR CONDITIONING & HEAT
Mitsubishi - A/C System General Servicing
Diamante, Eclipse, Galant, Mirage, Montero, Montero Sport &
3000GT
A/C COMPRESSOR APPLICATIONS
A/C COMPRESSOR APPLICATION TABLE \
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Application Compressor
Diamante ......................... Sanden MSC105CVS Scroll
Eclipse
2.0L Non-Turbo ............. Nippondenso 10PA17C 10-Cyl.
2.0L Turbo & 2.4L .............. Sanden MSC105CVS Scroll
Galant ............................ Sanden MSC90C12 Scroll
Mirage ............................... Sanden MSC90 Scroll
Montero ....................... Nippondenso 10PA15 10-Cyl.
Montero Sport ...................... Sanden MSC105C Scroll
3000GT .............................. Sanden MSC105 Scroll
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USING R-12 & R-134a REFRIGERANT
HANDLING/SAFETY PRECAUTIONS
1) Always work in a well-ventilated, clean area. Avoid
breathing refrigerant vapors. Exposure may irritate eyes, nose and
throat. Refrigerant is colorless and is invisible as a gas.
Refrigerant is heavier than oxygen and will displace oxygen in a
confined area.
2) A/C system high pressure can cause severe injury to eyes
and skin if a hose were to burst. Always wear eye protection, gloves
and other protective clothing when working around A/C system and
refrigerant.
3) Refrigerant evaporates quickly when exposed to atmosphere,
freezing anything it contacts. If liquid refrigerant contacts eyes or
skin (frostbite), DO NOT rub eyes or skin. Immediately flush affected
area with cool water for 15 minutes and consult a doctor or hospital.
4) Never use R-134a in combination with compressed air for
leak testing. Pressurized R-134a in the presence of oxygen (air
concentrations greater than 60 percent by volume) may form a
combustible mixture. DO NOT introduce compressed air into R-134a
containers (full or empty), A/C system components or service
equipment.
5) DO NOT expose A/C system components to high temperatures,
steam cleaning for example, as excessive heat will cause
refrigerant/system pressure to increase. Never expose refrigerant
directly to open flame. If refrigerant needs to be warmed, place
bottom of refrigerant tank in warm water. Water temperature MUST NOT
exceed 125
F (52C).
CAUTION: When R-134a is exposed to an open flame, drawn into engine,
or detected with a Halide (propane) leak tester, a poisonous
gas is formed. Keep work areas well ventilated.
6) Use care when handling refrigerant containers. DO NOT
drop, strike, puncture or incinerate containers. Use Department Of
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Symptom Inspection Procedure
Communication With All Systems Not Possible ............ 1
Communication With SRS Only Not Possible ............... 2
Ignition Switch On (Engine Stopped)
SRS Warning Light Does Not Come On ............... DTC 43
SRS Warning Light Stays On After 7 Seconds ...... DTC 43
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INSPECTION PROCEDURE 1
The cause is probably in power supply system (including
ground circuit of diagnostic line). Check connectors and harness, and
repair if necessary.
INSPECTION PROCEDURE 2
NOTE: Refer to WIRING DIAGRAMS for connector identification.
1) Before proceeding, see SERVICE PRECAUTIONS. Deactivate
SRS. See DISABLING & ACTIVATING AIR BAG SYSTEM .
2) Measure SRS Check Harness (MB991613) connector No. 5.
Disconnect SRS-ECU connector C-122 and connect SRS check harness
connector No. 3 to C-122. Check continuity between terminal No. 20, 21
and ground. If there is no continuity, go to next step. If there is
continuity, go to step 4).
3) Check connector C-122, and repair if necessary. If
connector is okay, check for trouble symptoms. If fault exists, check
harness between SRS-ECU and ground, and repair if necessary.
4) Measure SRS check harness connector No. 5. Disconnect SRS-
ECU connector C-122 and connect SRS harness check connector No. 3 to
C-122. Connect negative battery cable. Measure voltage between
terminal No. 13 and 14, and body ground. If voltage at terminals is 9
volts or more, check harness wire between SRS-ECU and Data Link
Connector (DLC), and repair if necessary. If harness wire is okay,
replace SRS-ECU. See SRS AIR BAG CONTROL UNIT (ECU) under REMOVAL &
INSTALLATION. If voltage is not as specified, check connector C-80, C-
93, C-101, and C-132, and repair if necessary. If connectors are okay,
check for trouble symptoms. If fault exists, check harness between
SRS-ECU and IG1 A or B (ignition switch), and repair if necessary.
Fig. 10: Identifying SRS Check Harness (MB991613) Connectors
Courtesy of Mitsubishi Motor Sales of America.
DTC 11, 12 & 13: FRONT IMPACT SENSOR SYSTEM