GENERAL DESCRIPTION
HEATER, AIR CONDITIONING AND VENTILATION55-3
GENERAL DESCRIPTIONM1552000100351
The heater and cooling units are combined in a sin-
gle unit, which, with the mode film damper and flow
rate control valve in the heater unit, reduces ventila-
tion resistance, increases fan power, and decreases
noise.
SAFETY PRECAUTIONS
Wear safety goggles and gloves when servic-
ing the refrigeration system to prevent
severe damage to eyes and hands.
Because R-134a refrigerant is a hydro fluorocarbon
(HFC) which contains hydrogen atoms in place of
chlorine atoms, it will not cause damage to the ozone
layer.
Ozone filters out harmful radiation from the sun. To
assist in protecting the ozone layer, Mitsubishi
Motors Corporation recommends an R-134a refriger-
ant recycling device.
Refrigerant R-134a is transparent and colorless in
both the liquid and vapor state. Since it has a boiling
point of
29.8C (21.64F) at atmospheric pressure,
it will be a vapor at all normal temperatures and pres-
sures. The vapor is heavier than air, non-flammable,
and non-explosive. The following precautions must
be observed when handling R-134a.
Do not heat R-134a above 40C (104.0F) or it
may catch fire and explode.
R-134a evaporates so rapidly at normal atmospheric
pressures and temperatures that it tends to freeze
anything it contacts. For this reason, extreme care
must be taken to prevent any liquid refrigerant from
contacting the skin and especially the eyes. Always
wear safety goggles when servicing the refrigeration
part of the A/C system. Keep a bottle of sterile min-
eral oil handy when working on the refrigeration sys-
tem.1. If any liquid refrigerant gets into your eyes, use a
few drops of mineral oil to wash them out. R-134a
is rapidly absorbed by the oil.
2. Next, splash your eyes with plenty of cold water.
3. Call your doctor immediately even if irritation has
ceased.
Keep R-134a containers upright when charging
the system.
In most instances, moderate heat is required to bring
the pressure of the refrigerant in its container above
the pressure of the system when charging or adding
refrigerant.
A bucket or large pan of hot water not over 40
C
(104.0
F) is all the heat required for this purpose. Do
not heat the refrigerant container with a blow torch or
any other means that would raise temperature and
pressure above this temperature. Do not weld or
steam-clean on or near the system components or
refrigerant lines.
A leak detector for R-134a should be used to
check for refrigerant gas leaks.
Do not allow liquid refrigerant to touch bright
metal or it will be stained.
When metering R-134a into the refrigeration system,
keep the supply tank or cans in an upright position. If
the refrigerant container is on its side or upside
down, liquid refrigerant will enter the system and
damage the compressor.
Refrigerant will tarnish bright metal and chrome sur-
faces, and in combination with moisture can severely
corrode all metal surfaces. ITEM SPECIFICATION
Heater control assembly Dial type
Compressor 10S17
Compressor Model Swashplate type
Refrigerant and quantity (g) R-134a (HFC-134a), 435
475
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-76
MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A (Vehicles with CAN
communication system)
STEP 1. Check the defogger and outside/inside air
selection damper control motor operation.
Q: Do the defogger and outside/inside air selection damper
control motor work normally?
YES : Go to Step 2.
NO : Refer to Inspection procedure 10, "Malfunction of the
A/C-ECU power supply system P.55-122."
STEP 2. Check the blower motor operation.
Q: Does the blower motor work normally?
YES : Go to Step 3.
NO : Refer to Inspection procedure 5, "Front blower fan
and motor do not turn P.55-89."
STEP 3. Check the A/C compressor.
Check the A/C compressor for compressor oil leaks.
Q: Is the check result satisfactory?
YES : Go to Step 4.
NO : Replace the A/C compressor or the expansion valve.
STEP 4. Using scan tool , read the A/C diagnostic trouble
code.
Check if an A/C-ECU DTC is set.
(1) Connect scan tool to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?
YES : Go to Step 5.
NO : Refer to DIAGNOSTIC TROUBLE CODE CHART
P.55-9.
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-112
STEP 4. Check choke coil connector D-11 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is choke coil connector D-11 in good condition?
YES : Go to Step 5.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. The
defogger system should work normally.
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-119
STEP 12. Check the wiring harness between defogger
relay connector C-201 (terminal 4) and choke coil
connector D-11 (terminal 1).
NOTE: Also check junction block connector C-204 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-204 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between defogger relay connector
C-201 (terminal 4) and choke coil connector D-11
(terminal 1) in good condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair or replace the wiring harness. Refer to
GROUP 00E, Harness Connector Inspection
P.00E-2. Check that the defogger system works
normally.
STEP 13. Check choke coil connector D-11 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is choke coil connector D-11 in good condition?
YES : Go to Step 14.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Check
that the defogger system works normally.
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-120
STEP 14. Check the wiring harness between choke coil
connector D-11 (terminal 1) and rear glass solder joint.
Q: Is the wiring harness between choke coil connector
D-11 (terminal 1) and rear glass solder joint in good
condition?
YES : Go to Step 15.
NO : Repair or replace the wiring harness. Refer to
GROUP 00E, Harness Connector Inspection
P.00E-2. Check that the defogger system works
normally.
STEP 15. Check rear glass solder joints for loose,
corroded or damaged joints.
Q: Are solder joints in good condition?
YES : Go to Step 16.
NO : Repair solder joint. Check that the defogger system
works normally.
STEP 16. Check the wiring harness between RH rear glass
solder joint and earth point.
Q: Is the wiring harness between RH rear glass solder joint
and earth point in good condition?
YES : Go to Step 17.
NO : Repair or replace the wiring harness or repair solder
joint. . Check that the defogger system works
normally.
ON-VEHICLE SERVICE
HEATER, AIR CONDITIONING AND VENTILATION55-142
4. At this time, check to see that the voltage of A/C pressure
sensor terminal No. 2 reflects the specifications of the fig-
ure.
NOTE: The allowance shall be defined as
5%.
COMPRESSOR DRIVE BELT ADJUSTMENTM1552001000357
Refer to GROUP 00, Maintenance Service Drive Belts
P.00-39.
CHARGING M1552001200403
Use the refrigerant recovery station to charge the refrigerant.
METHOD BY USING REFRIGERANT RECOVERY
AND RECYCLING UNIT
Using the refrigerant recovery and recycling unit, refill the
refrigerant.
NOTE: Refer to the Refrigerant Recovery and Recycling Unit’s
Instruction Manual for operation of the unit.
DISCHARGING SYSTEM
Use the refrigerant recovery unit to discharge refrigerant gas
from the system.
NOTE: Refer to the Refrigerant Recovery and Recycling Unit’s
Instruction Manual for operation of the unit.
REFILLING OF OIL IN THE A/C SYSTEM
Too little oil will provide inadequate compressor lubrication and
cause a compressor failure. Too much oil will increase dis-
charge air temperature.
When a compressor is installed at the factory, it contains 140
ml of refrigerant oil. While the A/C system is in operation, the oil
is carried through the entire system by the refrigerant. Some of
this oil will be trapped and retained in various parts of the sys-
tem.
When the following system components are changed, it is nec-
essary to add oil to the system to replace the oil being removed
with the component.
Compressor oil: ND Oil 8
Quantity:
Evaporator: 40 ml
Condenser: 40 ml
ON-VEHICLE SERVICE
HEATER, AIR CONDITIONING AND VENTILATION55-147
TEST PROCEDURES
1. Select a quiet area for testing.
2. Duplicate problem (customer complaint) as much as
possible.
3. Judge if the noise is abnormal (ie. it is important to
understand the characteristics of the vehicle and its normal
state to judge what is abnormal) - Compare with similar
vehicle if necessary.
4. Detail what and how noise occurs.
5. Find the noise source and verify its transmission by isolating
the subject part from the vehicle.
6. Repair the problem.
7. Explain and report your findings.
DETAILS OF A/C NOISE
POSSIBLE CAUSES, CHECKS AND REPAIRS
NOISE DESCRIPTION WHEN IT OCCURS SOURCE OF NOISE
Rumbling (Bearing noise) With A/C On or Off Magnetic clutch, idler pulley
Clang-Clack noise When compressor is engaged Magnetic clutch operation
Squawking (Belt sliding noise) When compressor is engaged V-belt
Whistling or Whooping noise Immediately after the A/C is
engaged.Expansion valve
Hissing or swishing noise When A/C is engaged, but
decreases as flow is stable Refrigerant flow
Rattling (Internal compressor) When compressor is operating Compressor internal part
Wooing (Resonant noise) With A/C On, occurs at certain
speed.Resonance of accessories
Cooing (Discharge pulsation
noise)With A/C On or Off Resonating noise with the vehicle
body
NOISE DESCRIPTION POSSIBLE CAUSE CHECK REPAIR
Rumbling (Bearing
noise)Bearing damage in rotor Manual rotation of bearing Replace compressor
Rotor slipping on boss Wear on compressor boss
surfaceReplace compressor
Bearing damage in pulley Check alignment between
pulleysReplace compressor
Clang-Clack noise Hub to stator misaligned Wear on inner clutch face Replace compressor
Gap between clutch
surface is too largeCheck Air gap is within
specificationReplace compressor
Squawking (Belt sliding
noise)Oil/water between the belt
and rotor surfaceOil and water
contaminationClean
Low belt tension Belt tension Reset or Replace belt and
set tension to correct
specification
Whistling or Whooping
noiseVibration of expansion
valveExpansion valve Replace TX valve
ON-VEHICLE SERVICE
HEATER, AIR CONDITIONING AND VENTILATION55-148
POWER RELAY CHECKM1552008800321
BLOWER RELAY CONTINUITY CHECK
Hissing or swishing
noiseLow refrigerant quantity Refrigerant level Check system for leaks
and charge to
specification
Rattling (Internal
compressor)Lack of lubricating oil. In a
system with a gas leak
the oil has escaped with
the refrigerantRattling noise from
internal compressorRepalce the compressor
and also fix the system
leak to prevent
reoccurrance
Wooing (Resonant
noise)Drive accessory (P/S
pump, Alternator,etc)
resonating at specific
engine speedThe drive accessories for
vibrationStop vibrations of the
assembly or modify
transmission route to the
vehicle body
Cooing (Discharge
pulsation noise)Pressure fluctuation of
refrigerant discharged
from compressor, which
vibrates the high pressure
pipingRemove the piping
mounting clamps and
re-check. Hold the
condenser without
mountings by hand and
re-checkPut rubber bush between
pipe clamps and the
vehicle body. decrease
refrigerant to minimum
specified level. NOISE DESCRIPTION POSSIBLE CAUSE CHECK REPAIR
BATTERY
VOLTAGETESTER
CONNECTIONSPECIFIED
CONDITION
Not applied 4
5 Open circuit
Connect
terminal 1 to the
positive battery
terminal
Connect
terminal 3 to the
negative battery
terminal4
5 Less than 2 ohms