1991 MITSUBISHI MONTERO sensor

\003
A/C -H EA TE R S YSTE M - M AN UAL

1991 M it s u bis h i M onte ro
1991 MANUAL A/C-HEATER SYSTEMS
Chrysler Motors, Mitsubishi
Chrysler Motors: Colt Vista, Ram-50
Mitsubishi: Montero, Pickup
* PLEASE READ THIS FIRST *
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
A/C SYSTEM SPECIFICATIONS
SPECIFICATIONS TABLE








\









\









\









\









\









\









\


Compressor Type
Colt Vista & Montero .................... Nippondenso 10-Cyl.
Pickup & Ram-50 ............................... Sanden Scroll
Compressor Belt Deflection
Colt Vista ............................ 11/32-7/16" (8-11 mm)
Montero ............................. 21/64-3/8" (8.5-9.5 mm)
Pickup & Ram-50 .................... 21/64-25/64" (8.5-10 mm)
Compressor Oil Capacity
Colt Vista & Montero ............................... 2.7 ozs.
Pickup & Ram-50 .................................... 5.0 ozs.
Refrigerant (R-12) Capacity
Colt Vista & Montero ................................ 32 ozs.
Pickup & Ram-50 ..................................... 30 ozs.
System Operating Pressures (1)
Colt Vista, Pickup & Ram-50
High Side .................... 130-220 psi (9.1-15.5 kg/cm
)
Low Side ........................ 20-26 psi (1.4-1.8 kg/cm)
Montero
Dual Unit
High Side .................. 142-199 psi (9.9-14.0 kg/cm
)
Low Side ...................... 16-30 psi (1.1-2.1 kg/cm)
Single Unit
High Side ................... 102-142 psi (7.1-9.9 kg/cm
)
Low Side ...................... 18-32 psi (1.3-2.2 kg/cm)
(1) - With ambient temperature at least 80
F (27C).








\









\









\









\









\









\









\


DESCRIPTION
Slight variations exist among the manual A/C-heater systems
used. Either Sanden Scroll or Nippondenso 10-cylinder compressor is
used. Cycling of the compressor clutch is controlled by switches which
monitor temperatures and pressures.
Compressors will only operate within the normal operating
temperatures and pressures set for each model. An electric condenser
fan operates whenever A/C system is operating. System components used
vary depending upon model. Most systems include an A/C compressor
control unit, fan switch, evaporator, temperature sensor, high and low
(or dual) pressure switch, engine coolant temperature switch,
compressor, condenser, receiver-drier and various pipes and hoses.

Check blower switch and relay. Check A/C compressor clutch coil.
2) Ensure system is properly charged with correct amount of
refrigerant. Add refrigerant or evacuate and recharge 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 compressor 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. Add refrigerant or evacuate
and recharge 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.
INTERMITTENT COOL AIR
Check for air or moisture in system. Evacuate and recharge
system as necessary. Check for expansion valve malfunction. Replace
expansion valve if necessary. Check compressor belt for proper
tension.
TESTING
A/C SWITCH
1) Disconnect A/C switch harness connector. Using appropriate
wiring diagram as a guide, jumper appropriate terminals of A/C switch
wiring harness connector. See Fig. 4.
2) Turn blower on and momentarily turn ignition on without
starting engine. Listen for compressor clutch engagement. If
compressor clutch does not engage, check fuse and other components
wired in series with compressor clutch.
Fig. 4: A/C Switch Connector ID
Courtesy of Mitsubishi Motor Sales of America.
AIR THERMO & AIR INLET SENSORS

1) Disconnect sensor connector at evaporator case. Using an
ohmmeter, measure continuity between sensor terminals. See AIR THERMO
& AIR INLET SENSORS SPECIFICATIONS table.
2) If resistance is not within specifications, sensor is
faulty and must be replaced. If resistance is within specifications
and all other components are okay, replace A/C compressor control unit
(if equipped).
AIR THERMO & AIR INLET SENSORS SPECIFICATIONS TABLE









\









\









\









\









\









\

Sensor Temperature Ohms
Air Thermo Sensor
32
F (0C) .................................. 11,400
50F (10C) ................................... 7320
68F (20C) ................................... 4860
86F (30C) ................................... 3310
104F (40C) .................................. 2320
Air Inlet Sensor
32
F (0C) .................................... 3310
50F (10C) ................................... 2000
68F (20C) ................................... 1250
86F (30C) .................................... 810
104F (40C) .................................... 530








\









\









\









\









\









\

BLOWER RESISTOR
Disconnect blower resistor connector. Using an ohmmeter,
measure resistance between terminals indicated in BLOWER RESISTOR
RESISTANCE table. See Fig. 5.
BLOWER RESISTOR RESISTANCE TABLE









\









\









\









\









\









\

Terminal Ohms
Colt Vista
1 & 2 ................................ Approx. 1.22
1 & 3 ................................ Approx. 0.41
1 & 4 ................................ Approx. 2.65
1 & 5 ................................... Approx. 0
Montero (Front)
1 & 2 ................................ Approx. 1.22
1 & 3 ................................ Approx. 0.41
1 & 4 ................................ Approx. 2.25
1 & 5 ................................... Approx. 0
Montero (Rear)
2 & 4 ................................. Approx. 0.5
1 & 4 ................................. Approx. 1.8
3 & 4 ................................. Approx. 3.3
Pickup & Ram-50
1 & 2 ................................ Approx. 1.19
1 & 3 ................................ Approx. 0.50
1 & 4 ................................ Approx. 2.33
1 & 5 ................................... Approx. 0









\









\









\









\









\









\

COMPRESSOR CLUTCH
Disconnect wiring to compressor clutch. Connect battery
voltage directly to A/C compressor clutch wiring harness connector
terminals. If a click is heard, clutch engagement is okay. If click is
not heard, pulley and armature are not making contact. Repair or
replace as necessary.
REAR BLOWER SWITCH
Montero
With blower switch in position indicated in REAR BLOWER
SWITCH CONTINUITY TEST table, ensure continuity exists between
terminals listed. See Fig. 8.
REAR BLOWER SWITCH CONTINUITY TEST TABLE









\









\









\









\









\





Switch Terminal
Position Numbers Continuity
OFF ................. 1-6 ................. No
Low .............. 1, 2 & 6 .............. Yes
Medium 1 ......... 1, 3 & 6 .............. Yes
Medium 2 ......... 1, 4 & 6 .............. Yes
High ............. 1, 5 & 6 .............. Yes









\









\









\









\









\





Fig. 8: Identifying Rear Blower Switch Terminals (Montero)
Courtesy of Mitsubishi Motor Sales of America.
REFRIGERANT TEMPERATURE SENSOR
Disconnect refrigerant temperature sensor electrical
connector. Using an ohmmeter, measure resistance between terminals. At

77F (25C) resistance should be approximately 80,470 ohms. If
resistance deviates greatly, replace sensor.
RELAYS
4-Terminal Relay
1) Either round or square relays may be used. Testing is same
for either relay. Remove relay from holder. Using an ohmmeter, ensure
continuity exists between terminals No. 2 and 4 and does not exist
between terminals No. 1 and 3. See Fig. 9.
2) Connect battery voltage to terminal No. 2, and ground
terminalNo. 4. Ensure continuity exists between terminals No. 1 and 3.
If continuity is not as specified, replace relay.
Fig. 9: Testing 4-Terminal Relays
Courtesy of Mitsubishi Motor Sales of America.
6-Terminal Relay
Remove relay from holder. Using an ohmmeter, ensure

HEATER HOSES
HIGH PRESSURE RELIEF VALVES (HPRV)
IDLERS
IN-LINE FILTERS
METAL FITTINGS
METAL LINES
MIX AND AIR CONTROL DOORS (BLEND DOORS)
O-RINGS
ORIFICE TUBES
PILOT-OPERATED ABSOLUTES (POAS)
PLENUMS
PRESSURE CONTROL VALVES
PRESSURE SENSORS
PULLEYS
RADIATORS
RECEIVER-DRIERS
REFRIGERANT
REFRIGERANT OIL
RELAYS
SEALS
SERVICE PORTS
SPRING LOCK COUPLINGS
SUCTION THROTTLING VALVES (STVS)
SWITCHES (ELECTRICAL)
TENSIONERS
THERMISTORS AND PRESSURE SENSORS
THERMOSTATS AND HOUSINGS
VACUUM HOSES AND TUBES
VACUUM RESERVOIRS
VACUUM TUBES
VALVES IN RECEIVER (VIRS)
WATER PUMPS (ELECTRIC AUXILIARY)
WIRING HARNESSES AND CONNECTORS
MOTORIST ASSURANCE PROGRAM (MAP)
OVERVIEW
The Motorist Assurance Program is the consumer outreach
effort of the Automotive Maintenance and Repair Association, Inc.
(AMRA). Participation in the Motorist Assurance Program is drawn from
retailers, suppliers, independent repair facilities, vehicle
manufacturers and industry associations.
Our organization's mission is to strengthen the relationship
between the consumer and the auto repair industry. We produce
materials that give motorists the information and encouragement to
take greater responsibility for their vehicles-through proper,
manufacturer-recommended, maintenance. We encourage participating
service and repair shops (including franchisees and dealers) to adopt
(1) a Pledge of Assurance to their Customers and (2) the Motorist
Assurance Program Standards of Service. All participating service
providers have agreed to subscribe to this Pledge and to adhere to the
promulgated Standards of Service demonstrating to their customers that
they are serious about customer satisfaction.
These Standards of Service require that an inspection of the
vehicle's (problem) system be made and the results communicated to the\
customer according to industry standards. Given that the industry did
not have such standards, the Motorist Assurance Program successfully
promulgated industry inspection communication standards in 1994-95 for
the following systems: Exhaust, Brakes, ABS, Steering and Suspension,
Engine Maintenance and Performance, HVAC, and Electrical Systems.
Further, revisions to all of these inspection communication standards

\









\









\









\









\









\









\


Condition Code Procedure
Air control door
binding ................ A ... Require repair or replacement
Air control door
broken ................. A .. Require repair or replacement.
Air control door
leaking ................ A .. Require repair or replacement.
Air control door
seized ................. A .. Require repair or replacement.
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Cracked ................. 2 .. Suggest repair or replacement.
Drain hole restricted ... A ................. Require repair.
Drain plugged ........... A ................. Require repair.
Duct disconnected ....... A .. Require repair or replacement.
Duct leaking ............ A .. Require repair or replacement.
Duct missing ............ C ............ Require replacement.
Duct restricted ......... A .. Require repair or replacement.
Leaking ................. A .. Require repair or replacement.
Noisy ................... 2 ..... Suggest cleaning or repair.
Odor .................... 2 ..... Suggest cleaning or repair.
Restricted .............. A .... Require cleaning, repair, or
replacement.









\









\









\









\









\









\









\


PRESSURE CONTROL VALVES
See:
* EVAPORATOR PRESSURE REGULATORS (EPRS)
* HIGH PRESSURE RELIEF VALVES (HPRV)
* PILOT-OPERATED ABSOLUTES (POAS)
* SUCTION THROTTLING VALVES (STVS)
* VALVES IN RECEIVER (VIRS)
PRESSURE SENSORS
See THERMISTORS AND PRESSURE SENSORS .
PULLEYS
PULLEY INSPECTION








\









\









\









\









\









\









\


Condition Code Procedure
Alignment incorrect ..... B .. Require repair or replacement.
Application incorrect ... B ............ Require replacement.
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not

Alignment incorrect ..... B .. Require repair or replacement.
Application incorrect ... B ............ Require replacement.
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Bearing worn ............ 1 ............ Suggest replacement.
Belt tension incorrect .. B ... Require adjustment or repair.
Bracket cracked ......... A .. Require repair or replacement.
Housing cracked ......... A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Noisy ................... 2 ............ Suggest replacement.
Pulley damaged, affecting
belt life .............. A ............ Require replacement.
Seized .................. A .. Require repair or replacement.









\









\









\









\









\









\









\


THERMISTORS AND PRESSURE SENSORS
NOTE: Includes, but not limited to, In-Car Temperature, Ambient
Air Temperature, Sun Load Sensor, etc.
THERMISTOR AND PRESSURE SENSOR INSPECTION









\









\









\









\









\









\









\


Condition Code Procedure
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Calibration incorrect ... B .. Require repair or replacement.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted,
affecting performance .. A ........... ( 1) Require repair or
replacement.
Connector melted, not
affecting performance .. 2 ........... ( 1) Suggest repair or
replacement.
Connector missing ....... C ............ Require replacement.
Inoperative ............. A ........... ( 2) Require repair or
replacement.
Missing ................. C ............ Require replacement.
Terminal burned, affecting
performance ............ A ........... ( 1) Require repair or
replacement.
Terminal burned, not
affecting performance ... 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.