1991 MITSUBISHI MONTERO diagram

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. 13: Exploded View of Rear Evaporator Assembly (Montero)
Courtesy of Mitsubishi Motor Sales of America.
Removal & Installation (Pickup & Ram-50)
Discharge A/C system using approved refrigerant
recovery/recycling equipment. Disconnect liquid pipe and suction hose
connections. Remove glove box assembly. Remove air and defroster
ducts. Remove evaporator drain hose and clamp. Disconnect wiring
connectors. Remove nut from firewall evaporator assembly mounting
bracket. Remove evaporator assembly. To install, reverse removal
procedure.
WIRING DIAGRAMS

Fig. 14: Manual A/C-Heater Wiring Diagram (Colt Vista)

Fig. 15: Manual A/C-Heater Wiring Diagram (Montero)

Fig. 16: Manual A/C-Heater Wiring Diagram (Pickup & Ram-50)

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F - B ASIC T E STIN G

1991 M it s u bis h i M onte ro
1991 ENGINE PERFORMANCE
Basic Diagnostic Procedures
Chrysler; Colt, Colt 200, Colt Vista, Ram-50, Stealth,
Summit
Mitsubishi; Eclipse, Galant, Mirage, Montero, Pickup, 3000GT
INTRODUCTION
The following diagnostic steps will help prevent overlooking
a simple problem. This is also where to begin diagnosis for a no start
condition. First step in diagnosing any driveability problem is
verifying customer's complaint with a test drive under conditions
problem reportedly occurred.
Before entering self-diagnostics, perform a careful and
complete visual inspection. Most engine control problems result from
mechanical breakdowns, poor electrical connections or
damaged/misrouted vacuum hoses. Before condemning computerized system,
perform each test listed in article.
NOTE: Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM)\
with a minimum 10-megohm input impedance, unless stated
otherwise in test procedure.
PRELIMINARY INSPECTION & ADJUSTMENTS
VISUAL INSPECTION
Visually inspect all electrical wiring, looking for chafed,
stretched, cut or pinched wiring. Ensure electrical connectors fit
tightly and are not corroded. Ensure distributor cap and rotor are
free of cracks, carbon trails or contamination. Ensure vacuum hoses
are properly routed and not pinched or cut. See M - VACUUM DIAGRAMS
article in the ENGINE PERFORMANCE Section to verify routing and
connections (if necessary). Inspect air induction system for possible
vacuum leaks.
MECHANICAL INSPECTION
Compression
Check engine mechanical condition with a compression gauge,
vacuum gauge, or an engine analyzer. See engine analyzer manual for
specific instructions.
WARNING: DO NOT use ignition switch during compression tests. Use a
remote starter to crank engine. Fuel injectors on many models
are triggered by ignition switch during cranking mode, which
can create a fire hazard or contaminate engine's oiling
system.
COMPRESSION SPECIFICATIONS TABLE (1)









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Application Specification
psi (kg/cm)
1.5L (VIN X) .............................. 137 (9.6)
1.6L (VIN Y) ............................. 171 (12.0)
1.8L (VIN T) .............................. 131 (9.2)

Fig. 16: 1992 Symptom Chart (2 Of 2)
Courtesy of Mitsubishi Motor Co.
CIRCUIT TESTS (1991)
NOTE: To identify circuit connector terminals, See Figs. 17-21.
For wiring diagram, See appropriate chassis wiring
diagram in the WIRING DIAGRAMS Setion.

Fig. 21: 1991 Acturator Connector
Courtesy of Mitsubishi Motor Co.
CIRCUIT TESTS (1992)
NOTE: To identify circuit connector terminals, See Figs. 22-29.
For wiring diagram, See appropriate chassis wiring diagram in
the WIRING DIAGRAMS Section.
Test No. 1 (Power & Ground Circuit)
1) Turn ignition on. When cruise control main switch is
turned to ON position, battery voltage should be present on terminal
No. 2 of cruise control unit connector.
2) If voltage is not present, check fuse No. 11 and replace
as necessary. If fuse is okay, check and repair harness as necessary.
Terminal No. 8 should be grounded at all times. If terminal No. 8 is
not grounded, repair harness.
Test No. 2 (Set Switch Circuits)
When set switch is turned to ON position, 3 volts should be
present on terminal No. 18 of cruise control unit. When set switch is
turned to OFF position, voltage should not be present on terminal No.
18 of cruise control unit. If circuit does not test correctly, replace
switch as necessary or repair harness.
Test No. 3 (Resume Switch Circuit)
When resume switch is turned to ON position, 6 volts should
be present on terminal No. 18 of cruise control unit. When resume
switch is turned to OFF position, voltage should not be present on
terminal No. 18 of cruise control unit. If circuit does not test
correctly, replace switch as necessary or repair harness.
Test No. 4 (Cancel Switch Circuit)
When cancel switch is turned to On position, battery voltage
should be present on terminal No. 18 of cruise control unit. When
cancel switch is in Off position, voltage should not be present on
terminal No. 18 of cruise control unit. If circuit does not test
correctly, replace switch as necessary or repair harness.