1991 MITSUBISHI MONTERO engine

speeds of blower operation are selected. In order for A/C system to
operate, blower motor control lever MUST be in a position other than
OFF.
MODE SELECTOR LEVER
Mode selector lever is located in upper right corner of
control panel. Either 2 or 6 modes are available to achieve desired
distribution of air from various outlets.
On all models, air is directed to windshield and side
windows and comes out from the panel outlets when mode selector lever
is positioned to the far left. When lever is moved one detent to the
right, air is directed to windshield and side windows simultaneously.
On 6-mode models, air is directed to floor area, windshield,
and side windows when lever is moved 2 detents to the right. When
lever is moved 3 detents to the right, air is directed to floor area.
When lever is moved to the second to last detent on control panel, air
is directed to floor area and panel outlets. When lever is in the far
right position, air will be directed to panel outlets only.
TEMPERATURE CONTROL LEVER
The temperature control lever operates blend-air door in the
heater/air conditioning unit, mixing cooled and heated air so the
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. The temperature control lever should be
in the far left (maximum cooling) side of temperature selection scale
when maximum A/C cooling is desired.
DUAL PRESSURE SWITCH
The dual pressure switch, located in the refrigerant line
near condenser, is wired in series with compressor clutch. Whenever
system pressures drop below or increase above the control point of the
switch, power supplied to compressor will be cut and compressor
activity will cease until pressures are back to within operating
ranges.
ENGINE COOLANT TEMPERATURE SWITCH
The 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.
EVAPORATOR THERMISTOR
The evaporator thermistor, attached to evaporator fins, is
wired in series with compressor clutch and prevents evaporator
freezing. Power to compressor clutch is cut if control temperature is
exceeded, allowing evaporator to thaw. When temperature returns to
operating range, thermistor allows power to compressor clutch.
FUSIBLE PLUG
A fusible plug, located on receiver-drier, melts and allows
refrigerant to escape when ambient temperatures in engine compartment
reach 221
F (105C). Once fusible plug has blown, it cannot be reused
and must be replaced.

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

Fig. 7: Front Blower Switch Terminal ID (Colt Vista & Montero)
Courtesy of Mitsubishi Motor Sales of America.
DUAL PRESSURE SWITCH
Montero, Pickup & Ram-50
1) Turn engine off. Disconnect harness connector at dual
pressure switch (located near condenser). Jumper harness connector.
Turn A/C switch and blower switch to ON positions. Momentarily turn
ignition on and listen for compressor clutch engagement.
2) If compressor clutch does not engage, check evaporator
thermistor and engine coolant temperature switch. Check for a faulty
fuse. Repair or replace components as necessary. If compressor clutch
engages, go to next step.
3) Connect manifold gauge set to system, and check operating
pressures. Dual pressure switch should allow compressor operation if
system pressure is 30-384 psi (2-27 kg/cm
). If dual pressure switch
does not operate within specified pressure range, discharge system
using approved refrigerant recovery/recycling equipment, and replace
switch.
4) After replacing switch, recharge system, and monitor
pressures for proper compressor operation. If dual pressure switch
cuts power to compressor clutch while driving even though temperatures
inside have not yet decreased, high pressure side of dual pressure
switch has possibly been activated. Go to next step.
5) Discharge system using approved refrigerant
recovery/recycling equipment. Replace switch, and recharge system.
Ensure compressor clutch operates within 30-384 psi (2-27 kg/cm
).
Check for sufficient system cooling.

ENGINE COOLANT TEMPERATURE SWITCH
1) Turn engine off. Disconnect connector at engine coolant
temperature switch. Jumper wires on harness side of connector. If
vehicle uses a single connector, ground connector.
2) Press A/C switch to ON position and turn blower switch to
ON position. Momentarily turn ignition on and listen for compressor
clutch engagement. Clutch should engage. If clutch does not engage,
check fuse and other components wired in series with compressor
clutch.
EVAPORATOR THERMISTOR
Disconnect connector and remove thermo relay from evaporator
core. Jumper wires on harness side connector. Turn A/C switch to ON
position and turn on blower. Momentarily turn ignition on and listen
for compressor clutch engagement. If clutch does not engage, check
fuse and other components wired in series with compressor clutch.
HIGH PRESSURE SWITCH
Colt Vista
Disconnect high pressure switch connector. Jumper wires on
harness side of connector. Momentarily turn ignition on and listen for
compressor clutch engagement. If clutch does not engage, check fuse
and other components wired in series with compressor clutch.
HIGH/LOW PRESSURE CUT-OFF SWITCH
Pickup & Ram-50
1) Turn engine off. Disconnect High/Low Pressure Cut-Off
(HLPCO) switch, located on refrigerant line near condenser. Jumper
HLPCO wiring harness connector. Turn A/C switch and blower switch to
ON positions. Momentarily turn ignition on and listen for compressor
clutch engagement.
2) If compressor clutch does not engage, check evaporator
thermistor and engine coolant temperature switch. Check for a faulty
fuse. Repair or replace as necessary. If compressor clutch engages, go
to next step.
3) Connect manifold gauge set to system, and check operating
pressures. HLPCO switch should allow compressor operation if system
pressure is 28-385 psi (1.9-27 kg/cm
). If HLPCO switch does not
operate within specified pressure range, discharge system using
approved refrigerant recovery/recycling equipment, and replace switch.
4) After replacing switch, recharge system, and monitor
pressures for proper compressor function. If HLPCO switch cuts power
to compressor clutch while driving even though temperatures inside
have not yet decreased, high pressure side of new HLPCO switch has
possibly been activated. Go to next step.
5) Discharge system using approved refrigerant
recovery/recycling equipment. Replace switch, and recharge system.
Ensure compressor clutch operates within 28-385 psi (1.9-27 kg/cm
).
Check for sufficient system cooling.
LOW PRESSURE SWITCH
Colt Vista
Disconnect low pressure switch connector. Jumper wires on
harness side of connector. Momentarily turn ignition on and listen for
compressor clutch engagement. If clutch does not engage, check fuse
and other components wired in series with compressor clutch.

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 attaching bolts in passenger
compartment. Remove evaporator assembly. See Fig. 12 or 13. To
install, reverse removal procedure.
Fig. 12: Exploded View of Front Evaporator (Montero)
Courtesy of Mitsubishi Motor Sales of America.

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

are continually republished. In addition to these, standards for Drive
Train and Transmissions have recently been promulgated. Participating
shops utilize these Uniform Inspection & Communication Standards as
part of the inspection process and for communicating their findings to
their customers.
The Motorist Assurance Program continues to work
cooperatively and proactively with government agencies and consumer
groups toward solutions that both benefit the customer and are
mutually acceptable to both regulators and industry. We maintain the
belief that industry must retain control over how we conduct our
business, and we must be viewed as part of the solution and not part
of the problem. Meetings with state and other government officials
(and their representatives), concerned with auto repair and/or
consumer protection, are conducted. Feedback from these sessions is
brought back to the association, and the program adjusted as needed.
To assure auto repair customers recourse if they were not
satisfied with a repair transaction, the Motorist Assurance Program
offers mediation and arbitration through MAP/BBB-CARE and other non-
profit organizations. MAP conducted pilot programs in twelve states
before announcing the program nationally in October, 1998. During the
pilots, participating repair shops demonstrated their adherence to the
Pledge and Standards and agreed to follow the UICS in communicating
the results of their inspection to their customers. To put some
"teeth" in the program, an accreditation requirement for shops was
initiated. The requirements are stringent, and a self-policing method
has been incorporated which includes the "mystery shopping" of
outlets.
We welcome you to join us as we continue our outreach... with
your support, both the automotive repair industry and your customers
will reap the benefits. Please visit MAP at our Internet site www.
motorist.org or contact us at:
1444 I Street, NW Suite 700
Washington, DC 20005
Phone (202) 712-9042 Fax (202) 216-9646
January 1999
MAP UNIFORM INSPECTION GENERAL GUIDELINES
OVERVIEW OF SERVICE REQUIREMENTS & SUGGESTIONS
It is MAP policy that all exhaust, brake, steering,
suspension, wheel alignment, drive-line, engine performance and
maintenance, and heating, ventilation and air conditioning, and
electrical services be offered and performed under the standards and
procedures specified in these sections.
Before any service is performed on a vehicle, an inspection
of the appropriate system must be performed. The results of this
inspection must be explained to the customer and documented on an
inspection form. The condition of the vehicle and its components will
indicate what services/part replacements may be "Required" or
"Suggested". In addition, suggestions may be made to satisfy the
requests expressed by the customer.
When a component is suggested or required to be repaired or
replaced, the decision to repair or replace must be made in the
customer's best interest, and at his or her choice given the options
available.
This section lists the various parts and conditions that
indicate a required or suggested service or part replacement.
Although this list is extensive, it is not fully inclusive. In
addition to this list, a technician may make a suggestion. However,
any suggestions must be based on substantial and informed experience,

Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
Wire lead shorted ....... A .. Require repair or replacement.
(1) - Refer to manufacturer's diagnostic trouble code
procedure and require repair or replacement of
affected component(s).
( 2) - Determine cause and correct prior to repair or
replacement of part.
( 3) - Determine source of contamination, such as engine coolant,
fuel, metal particles, or water. Require repair or
replacement. Check for accepted cleaning procedure.
( 4) - Inoperative includes intermittent operation or out of
OEM specification. Some components may be serviceable.









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COOLANT
COOLANT INSPECTION








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Condition Code Procedure
Acidity (pH) incorrect .. 1 ........... Suggest correction or
replacement.
Contaminated ............ B ...... ( 1) Require replacement or
recycling. Further
inspection required.
Level incorrect ......... B .......... ( 2) Require filling to
proper level.
Maintenance intervals ... 3 ........ ( 3) Suggest replacement.
Mixture incorrect ....... B ........... Require correction or
replacement.
Type incorrect .......... B ............ Require replacement.
( 1) - Determine source of contamination and require correction
prior to coolant replacement.
( 2) - Determine source of incorrect level and suggest repair.
( 3) - The system should be drained and/or flushed and
refilled with correct coolant according to OEM
recommended service interval and procedures.









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COOLING FAN BLADES
COOLING FAN BLADE INSPECTION








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Condition Code Procedure
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.