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.
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.
\003
* A /C -H EA TE R S YSTE M U NIF O RM IN SPEC TIO N G UID ELIN ES *
1 991 M it s u bis h i M onte ro
GENERAL INFORMATION
A/C-Heater System Motorist Assurance Program
Standards For Automotive Repair
All Makes and Models
INTRODUCTION TO MOTORIST ASSURANCE PROGRAM (MAP)
CONTENTS
Motorist Assurance Program (MAP)
OVERVIEW
OVERVIEW OF SERVICE REQUIREMENTS & SUGGESTIONS
Heating, Ventilation and Air Conditioning
ACCUMULATORS
ACTUATORS (ELECTRICAL)
ACTUATORS (VACUUM)
AIR CONDITIONING FITTINGS
AIR CONDITIONING HOSES
AIR CONDITIONING METAL LINES, HOSES AND FITTING ASSEMBLIES
AIR CONTROL DOORS
AIR DAMS (EXTERNAL)
AIR DISTRIBUTION SYSTEM
BELTS
BLEND DOORS
BLOWER FANS (BLOWER WHEEL OR SQUIRREL CAGE)
BLOWER MOTORS
BLOWER RESISTORS
BLOWER SWITCHES
CABIN AIR FILTERS
CIRCUIT BREAKERS
COMPRESSOR CLUTCH ASSEMBLIES
COMPRESSORS
CONDENSER AIR SEALS
CONDENSER FAN MOTORS
CONDENSERS
CONNECTORS
CONTROL CABLES
CONTROL HEADS (FUNCTION SELECTORS)
CONTROL LINKAGES
CONTROL MODULES
COOLANT
COOLING FAN BLADES
COOLING FAN CLUTCHES
COOLING FAN MOTORS
EVAPORATOR DRAIN TUBES
EVAPORATOR PRESSURE REGULATORS (EPRS)
EVAPORATORS
EXPANSION VALVES
FUNCTION SELECTORS
FUSES, FUSIBLE LINKS AND CIRCUIT BREAKERS
FUSIBLE LINKS
GASKETS
HEATER CASES
HEATER CONTROL VALVES
HEATER CORES
Missing ................. C ........... Require replacement.
Noisy ................... 2 . Suggest repair or replacement.
Out of adjustment ....... B .......... (1) Require repair or
replacement.
Seized .................. A . Require repair or replacement.
( 1) - Follow OEM recommended adjustment procedures. Require
repair or replacement if out of specification.
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CONTROL MODULES
NOTE: Includes, but not limited to: IRCM, Coolant Fan Control
Module (CFCM), AC Controller, Amplifier, Programmers,
Control Heads, Power Modules, etc.
CONTROL MODULE INSPECTION
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Condition Code Procedure
Application incorrect ... B ............ Require replacement.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware
threads damaged ........ A ... Require repair or replacement
of hardware.
Attaching hardware
threads stripped
(threads missing) ...... A ... Require repair or replacement
of hardware.
Code set
(if applicable) ........ A .......... ( 1) Further inspection
required.
Connector broken ........ A .. Require repair or replacement.
Connector melted,
affecting performance .. A ........... ( 2) Require repair or
replacement.
Connector melted, not
affecting performance .. 2 ........... ( 2) Suggest repair or
replacement.
Connector missing ....... A ................. Require repair.
Contaminated ............ A ........... ( 3) Require repair or
replacement.
Inoperative ............. B ........... ( 4) Require repair or
replacement. Further
inspection required.
Leaking ................. A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... ( 2) 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.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
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.
of hardware.
Binding ................. 2 .. Suggest repair or replacement.
Coolant leak ............ A .. Require repair or replacement.
Disconnected ............ A .. Require repair or replacement.
Malfunctioning .......... A ........... (1) Require repair or
replacement.
Missing ................. C ............ Require replacement.
Restricted .............. A .. Require repair or replacement.
Seized .................. A .. Require repair or replacement.
Vacuum leak ............. A .. Require repair or replacement.
( 1) - Includes inoperative, intermittent operation, or
failure to perform all functions.
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HEATER CORES
HEATER CORE INSPECTION \
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Condition Code Procedure
Air flow obstruction .... 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.
Connection leaking ...... A .. Require repair or replacement.
Corroded ................ 1 .. Suggest repair or replacement.
Disconnected ............ A .. Require repair or replacement.
Fins damaged, affecting
performance ............ A .. Require repair or replacement.
Fins damaged, not
affecting performance .. .. ........ No service suggested or
required.
Internal restrictions,
affecting performance .. A .. Require repair or replacement.
Leaking ................. A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
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HEATER HOSES
HEATER HOSE INSPECTION \
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Condition Code Procedure
Application incorrect ... B ............ Require replacement.
Connected incorrectly ... A ................. Require repair.
Corroded, not reusable .. 1 ............ Suggest replacement.
Cracked ................. A .. Require repair or replacement.
Hard (brittle) .......... 1 .. Suggest repair or replacement.
Inner fabric (webbing)
damaged ................ A ............ Require replacement.
Insufficient clamping
force, allowing hose to
leak ................... A .. Require repair or replacement.
Leaking ................. A .. Require repair or replacement.
Maintenance intervals ... 3 ............ Suggest replacement.
NOTE: Copied Vehicle Speed Sensors from Engine UIGs & added
Air Gap incorrect, loose, and wire lead misrouted. For
"contaminated" removed coolant & fuel examples from note.
SPEED SENSOR INSPECTION
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Condition Code Procedure
Air gap incorrect ....... B ....... (1) Require adjustment or
replacement.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware
threads damaged ........ A ... Require repair or replacement
of hardware.
Attaching hardware
threads stripped
(threads missing) ...... A .. Require repair or replacement
of hardware.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking ........... A .. Require repair or replacement.
Connector melted ........ A ........... ( 2) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Contaminated ............ A ........... ( 3) Require repair or
replacement.
Inoperative ............. B ........... ( 4) Require repair or
replacement. Further
inspection required.
Lead routing incorrect .. B ..... Require rerouting according
to vehicle manufacturer's
specifications.
Leaking ................. A .. Require repair or replacement.
Loose ................... A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Resistance out of
specification .......... B .. Require repair or replacement.
Sensor housing cracked .. 2 ............ Suggest replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned,
affecting performance .. A ........... ( 2) 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.
Terminal loose,
affecting performance .. B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
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 misrouted ..... B . Require re-routing according to
vehicle manufacturer's