Mitsubishi Montero (1998+). Manual - part 22

         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 (108



C) and

off at 235-243



F (112-118



C).

         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). Lever

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.

         ADJUSTMENTS

NOTE:    For adjustment procedures, see HEATER SYSTEM article.

         TROUBLE SHOOTING

         NO COOLING

         1) Ensure compressor clutch is operating. If compressor

clutch is operating, go to next step. If compressor clutch is not

operating, check fuses and A/C switch. Check dual-pressure switch.

Check air inlet sensor and air thermosensor. Check A/C compressor

relay. Check A/C compressor clutch coil. Check A/C control unit.

         2) Ensure system is properly charged with correct amount of

refrigerant. Evacuate and charge 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 components 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. Evacuate and charge 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. Check A/C compressor clutch coil.

         INTERMITTENT COOL AIR

         Check for air or moisture in system. Evacuate and charge

system as necessary. Check for expansion valve malfunction. Replace

expansion valve if necessary. Check compressor belt for proper

tension.

         TESTING

         * 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.

NOTE:    For testing procedures not covered in this article, see

         HEATER SYSTEM article.

         A/C SYSTEM PERFORMANCE

         1) Park vehicle out of direct sunlight. Install A/C gauge

set. Start engine and allow it to idle at 1000 RPM. Turn A/C on. Set

A/C controls to recirculated air, panel (vent) mode and full cold

settings.

         2) Set blower/fan on high speed. Close doors and windows.

Insert thermometer in center vent. Operate system for 20 minutes to

allow system to stabilize. Measure temperature.

         3) Discharge air temperature must be 37-44



F (3-7



C) at

center vent, with high side and low side pressures within

specification. See A/C SYSTEM SPECIFICATIONS table at beginning of

article.

         A/C CONTROL UNIT (ACCU)

         1) Locate A/C Control Unit (ACCU) on top of evaporator case

and disconnect 10-pin connector. Inspect connector and wiring for

damage. Turn ignition and A/C on. Set temperature control to maximum

cooling and blower switch to high. Using a DVOM set to appropriate

test function, inspect harness side of connector. See  Fig. 3. Go to

next step. If all test readings are as specified, replace ACCU.

         2) Terminal No. 1 (Green/Yellow wire) is ACCU output. With

A/C and blower motor on, battery voltage should be present when ACCU

has received signals from pressure and temperature sensors confirming

A/C operation is okay.

         3) Terminal No. 3 (Green/Blue wire) is ACCU power supply when

A/C switch is in A/C mode. With ignition and blower on, and A/C switch

at second level setting, battery voltage should be present.

         4) Terminal No. 5 (Green/Red wire) is ACCU power supply when

A/C switch is in ECONO mode. With ignition and blower on, and A/C

switch at first level setting, battery voltage should be present.

Terminals No. 2 and 7 (Black wire) are ACCU grounds. There should be

zero volts at all times.

         5) Turn ignition off. Reconnect 10-pin connector. Turn

ignition on. Turn A/C on. Set temperature control to maximum cooling

and blower switch to high. Backprobe 10-pin connector. Go to next

step. If all test readings are as specified, replace ACCU.

         6) Terminal No. 10 (Blue/White wire) is air thermosensor

power supply. With ignition, blower and A/C on, approximately 5.5

volts should be present.

         7) Terminal No. 8 (Blue/Yellow wire) is air thermosensor

signal. When temperature of evaporator outlet portion is 77



F (25



C),

there should be approximately 3.6 volts present.

         8) Terminal No. 4 (White/Blue wire) is air inlet sensor power

supply. With ignition, blower and A/C on, approximately 5.5 volts

should be present.

         9) Terminal No. 9 (Yellow/Green wire) is air inlet sensor

signal. When temperature of evaporator outlet portion is 77



F (25



C),

there should be approximately 1.5 volts present.

Fig. 1:  Testing ACCU

Courtesy of Mitsubishi Motor Sales of America.

         A/C SWITCH

         With A/C switch in indicated position, ensure continuity

exists between listed terminals. See appropriate A/C SWITCH CONTINUITY

TEST table. See Fig. 2.

A/C SWITCH CONTINUITY TEST TABLE

Switch Position          Terminal No.             Continuity

OFF  ......................  (1)  ......................  No

ECONO  ...................  1 & 3  ....................  Yes

A/C  ...................  1, 3 & 4  ...................  Yes

(1) - Continuity should not exist between any terminals.

Fig. 2:  Identifying A/C Switch Terminals

Courtesy of Mitsubishi Motor Sales of America.

         A/C ENGINE COOLANT TEMPERATURE SWITCH

         1) Disconnect A/C engine coolant temperature switch

connector. Remove A/C engine coolant temperature switch. Carefully

heat a pan of oil and hold coolant temperature switch up to threads in

oil. Coolant switch is normally closed (continuity exists).

         2) When oil reaches 235-243



F (112-118



C), coolant switch

should open (no continuity). Replace A/C engine coolant temperature

switch if it does not test as specified. See  Fig. 3.