1998 MITSUBISHI MONTERO air condition

A/C-HEATER SYSTEM
1998 Mitsubishi Montero
1998 AIR CONDITIONING & HEAT
Mitsubishi - A/C-Heater System
Montero
* 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.
A/C SYSTEM SPECIFICATIONS
A/C SYSTEM SPECIFICATIONS TABLE








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Application Specification
Compressor Type ............... Nippondenso 10PA15 10-Cyl.
Compressor Belt Deflection ( 1)
New .......................... 13/64-15/64" (5.1-6.0 mm)
Used ......................... 17/64-19/64" (6.6-7.5 mm)
Compressor Oil Capacity ..................... ( 2) 2.7 ozs.
Refrigerant (R-134a) Capacity ................. 21-23 ozs.
System Operating Pressures ( 4)
High Side ............... 149-213 psi (10.5-15.0 kg/cm
)
Low Side .................... 14-33 psi (1.0-2.3 kg/cm)
( 1) - With 22 lbs. (100 N.m) force applied midway on longest
span of belt.
( 2) - Use ND 8-OIL refrigerant oil.
( 3) - Use SUN PAG 56 refrigerant oil.
( 4) - With ambient temperature at about 80
F (27C).








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DESCRIPTION
Slight variations exist among manual A/C-heater systems used.
On Montero, a Nippondenso 10-cylinder compressor is used. Cycling of
compressor clutch is controlled by an automatic A/C Control Unit
(ACCU).
Compressors will only operate within normal temperatures and
pressures set for each model. An electric condenser fan operates
whenever A/C system is operating. System components may vary depending
upon model. Systems may include an ACCU, fan switch, evaporator,
temperature sensor, dual-pressure switch, engine coolant temperature
switch, compressor, condenser, receiver-drier and various pipes and
hoses.
OPERATION
A/C CONTROL UNIT (ACCU)
ACCU controls cycling of compressor clutch based on
information received from air thermosensor and air inlet sensor, dual-
pressure switch, A/C switch and A/C engine coolant temperature switch.
ACCU is attached to top of evaporator housing.

A/C SWITCH
When turned on, the A/C system will operate if blower motor
control lever is in a position other than OFF. When activated, A/C
switch allows A/C compressor clutch to engage and operate the
compressor.
A/C ENGINE COOLANT TEMPERATURE SWITCH
The A/C engine coolant temperature switch, located on
thermostat housing, is wired in series with compressor clutch. When
coolant temperature is greater than switch control temperature, power
to compressor is cut and compressor is turned off until temperature
returns to operating range. Switch will turn on at 226
F (108C) and
off at 235-243F (112-118C).
AIR SELECTOR LEVER
The lever moves horizontally to select source of air used
inside passenger compartment. Lever moves from position on left
(outside air mode) to position on right (recirculated air mode). Lev\
er
should be set in recirculated air mode for maximum A/C cooling.
BLOWER MOTOR CONTROL SWITCH
Blower motor control switch rotates to select blower motor
speeds. As switch is rotated from left or OFF position, increasing
speeds of blower operation are selected. In order for A/C system to
operate, blower motor control switch must be in a position other than
OFF.
MODE SELECTOR KNOB
Mode selector knob has six modes available to achieve desired
distribution of air from various outlets. When knob is rotated fully
to left (counterclockwise), airflow is directed to upper passenger
area. In second position (clockwise), airflow is directed to upper
passenger area and slightly to leg area. Position 3, directs air
mostly to leg area and slightly to upper passenger area. Position 4,
directs air exclusively to leg area. Position 5, directs air to leg
area and to windshield and door windows. Position 6, directs air
exclusively to windshield and door windows.
TEMPERATURE CONTROL KNOB
Temperature control knob operates blend-air door in
heater/air conditioning unit, mixing cooled and heated air so that
selected air temperature can be obtained. The system will provide
cooled air when A/C switch is in ON position and blower motor is in
any position other than OFF. Temperature control knob should be on far
left (maximum cooling) side of temperature selection scale when
maximum A/C cooling is desired.
DUAL-PRESSURE SWITCH
The dual-pressure switch, mounted on receiver-drier, is wired
in series with compressor clutch. Whenever system pressures drop below
or increase above control points of switch, power supplied to
compressor will be cut and compressor function will cease until
pressures are back to normal operating ranges.

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.

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

A/C SYSTEM SPECIFICATIONS
1998 Mitsubishi Montero
1998 AIR CONDITIONING & HEAT
Mitsubishi - A/C System Specifications
Montero
A/C SYSTEM SPECIFICATIONS
A/C SYSTEM SPECIFICATIONS TABLE








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Application Specification
Compressor Type ............... Nippondenso 10PA15 10-Cyl.
Compressor Belt Deflection ( 1)
New .......................... 13/64-15/64" (5.1-6.0 mm)
Used ......................... 17/64-19/64" (6.6-7.5 mm)
Compressor Oil Capacity ..................... ( 2) 2.7 ozs.
Refrigerant (R-134a) Capacity ................. 21-23 ozs.
System Operating Pressures ( 4)
High Side ............... 149-213 psi (10.5-15.0 kg/cm
)
Low Side .................... 14-33 psi (1.0-2.3 kg/cm)
( 1) - With 22 lbs. (100 N.m) force applied midway on longest
span of belt.
( 2) - Use ND 8-OIL refrigerant oil.
( 3) - Use SUN PAG 56 refrigerant oil.
( 4) - With ambient temperature at about 80
F (27C).








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cause accidental air bag deployment and personal injury.
NOTE: Refer to WIRING DIAGRAMS for connector identification.
1) Before proceeding, see SERVICE PRECAUTIONS. Deactivate
SRS. See DISABLING & ACTIVATING AIR BAG SYSTEM .
2) Disconnect passenger-side air bag connector C-107. Connect
SRS Check Harness (MB991613) connector No. 1 to passenger-side air bag\
connector. Erase DTC memory and check if DTCs 24, 25, or 64 are set.
If any of these DTCs are output, go to next step. If DTCs are not
output, replace passenger-side air bag module. See
PASSENGER-SIDE AIR BAG MODULE under REMOVAL & INSTALLATION.
3) Check connectors C-107 and C-122, and repair if necessary.
If connectors are okay, check trouble symptoms. If fault is still
present, check harness wire between passenger-side air bag module and
SRS-ECU, and repair if necessary. If harness wire is okay, replace
SRS-ECU. See SRS AIR BAG CONTROL UNIT (ECU) under REMOVAL &
INSTALLATION.
DTC 31 & 32: SRS-ECU CAPACITOR SYSTEM
Before proceeding, see SERVICE PRECAUTIONS. Replace SRS-ECU.
See SRS AIR BAG CONTROL UNIT (ECU) under REMOVAL & INSTALLATION.
DTC 34: CONNECTOR LOCK SYSTEM
NOTE: If vehicle condition returns to normal, DTC will be erased
and SRS warning light will return to normal.
NOTE: Refer to WIRING DIAGRAMS for connector identification.
Before proceeding, see SERVICE PRECAUTIONS. Check connector
C-122 and repair if necessary. If connector is okay, check for trouble
symptom. If fault exists, replace SRS-ECU. See
SRS AIR BAG CONTROL UNIT (ECU) under REMOVAL & INSTALLATION.
DTC 35: SRS-ECU SYSTEM (AFTER AIR BAG DEPLOYMENT)
Before proceeding, see SERVICE PRECAUTIONS. Replace SRS-ECU.
See SRS AIR BAG CONTROL UNIT (ECU) under REMOVAL & INSTALLATION.
DTC 41: IG1 (A) POWER CIRCUIT SYSTEM
NOTE: If vehicle condition returns to normal, DTC will be erased
and SRS warning light will return to normal.
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 terminal No. 20 and 21 for continuity
to 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 symptom. If fault exists, check
harness wire 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 and turn ignition switch to ON
position. If voltage between terminal No. 14 and body ground is 9

volts or more, replace SRS-ECU. See SRS AIR BAG CONTROL UNIT (ECU)
under REMOVAL & INSTALLATION. If voltage is not as specified, check
connector C-93, C-101, and C-132, and repair if necessary. If
connectors are okay, check for trouble symptoms. If fault still
exists, check harness wire between SRS-ECU and ignition switch IG1
(A), and repair if necessary.
DTC 42: IG1 (B) POWER CIRCUIT SYSTEM
NOTE: If vehicle condition returns to normal, DTC will be erased
and SRS warning light will return to normal.
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 terminal No. 20 and 21 for continuity
to 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 still exists,
check harness wire 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 and turn ignition switch to ON
position. If voltage between terminal No. 13 and body ground is 9
volts or more, 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, and C-101, and repair if necessary. If
connectors are okay, check for trouble symptoms. If fault still
exists, check harness wire between SRS-ECU and ignition switch IG1
(B), and repair if necessary.
DTC 43: SRS WARNING LIGHT CIRCUIT
NOTE: Refer to WIRING DIAGRAMS for connector identification.
Light Does Not Come On
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 terminal No. 20 and 21 for continuity
to 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 still exists,
check harness wire 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 and turn ignition switch to ON
position. Connect terminal No. 15 to body ground. If SRS warning light
comes on, replace SRS-ECU. See SRS AIR BAG CONTROL UNIT (ECU) under
REMOVAL & INSTALLATION. If SRS warning light does not come on, inspect
for blown bulb and repair if necessary. If bulb is okay, check
connector C-04, C-11, C-96, and C-101, and repair if necessary. If
connectors are okay, check for trouble symptoms. If fault still
exists, check harness wire between SRS-ECU and ignition switch IG1,
and repair if necessary. If harness wire is okay, replace combination

meter.
Light Does Not Turn Off
1) Before proceeding, see SERVICE PRECAUTIONS. Connect
negative battery cable and turn ignition switch to ON position. If SRS
warning light stays on when C-122 is disconnected, go to next step. If
SRS warning light turns off when C-122 is disconnected, replace SRS-
ECU. See SRS AIR BAG CONTROL UNIT (ECU) under REMOVAL & INSTALLATION.
2) Check connector C-122, and repair if necessary. If
connector is okay, check trouble symptoms. If fault still exists,
check wire harness between SRS-ECU and combination meter, and repair
if necessary.
DTC 44: SRS WARNING LIGHT DRIVE CIRCUIT SYSTEM
NOTE: If vehicle condition returns to normal, DTC will be erased
and SRS warning light will return to normal.
Before proceeding, see SERVICE PRECAUTIONS. Check SRS warning
light drive circuit system. If warning light drive system is okay,
replace SRS-ECU. See SRS AIR BAG CONTROL UNIT (ECU) under REMOVAL &
INSTALLATION. Check for DTCs. See SYSTEM OPERATION CHECK.
DTC 45: SRS-ECU EEPROM & A/D CONVERTER SYSTEM
Before proceeding, see SERVICE PRECAUTIONS. Replace SRS-ECU.
See SRS AIR BAG CONTROL UNIT (ECU) under REMOVAL & INSTALLATION.
DTC 51 & 52: DRIVER-SIDE AIR BAG MODULE (SQUIB IGNITION
DRIVE CIRCUIT) SYSTEM
Before proceeding, see SERVICE PRECAUTIONS. Replace SRS-ECU.
See SRS AIR BAG CONTROL UNIT (ECU) under REMOVAL & INSTALLATION.
DTC 54 & 55: PASSENGER-SIDE AIR BAG MODULE (SQUIB
IGNITION DRIVE CIRCUIT) SYSTEM
Before proceeding, see SERVICE PRECAUTIONS. Replace SRS-ECU.
See SRS AIR BAG CONTROL UNIT (ECU) under REMOVAL & INSTALLATION.
COMPONENT TESTING
CLOCKSPRING TEST
1) Before proceeding, see SERVICE PRECAUTIONS. Deactivate
system. See DISABLING & ACTIVATING AIR BAG SYSTEM .
2) Remove driver-side air bag module and clockspring. See
DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING under REMOVAL & INSTALLATION.
Check connectors, protective tubing, and case for damage, and
terminals for deformities. Check for continuity between No. 1
connector of clockspring and connectors No. 3 and 4. See Figs. 12 and
13.
3) Align paint mark of SRS Check Harness (MB991613) connecto\
r
No. 4 with notch in clockspring connector No. 2 and connect. See
Fig. 14 . Check continuity between terminals No. 22 and 23 of SRS check
harness connector No. 5. See Fig. 13.
4) Replace clockspring if any damage was found or continuity
does not exist between specified terminals. See
DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING under REMOVAL & INSTALLATION.