Downloaded from www.Manualslib.com manuals search engine 1B-6 AIR CONDITIONING (OPTIONAL)
Cool air won’t come
out or insufficient
cooling (A/C system
normal operative)Insufficient or excessive charge of
refrigerantCheck charge of refrigerant and system for
leaks.
Condenser clogged Check condenser.
A/C evaporator clogged or frosted Check A/C evaporator and A/C evaporator
thermistor.
A/C evaporator thermistor faulty Check A/C evaporator thermistor.
Expansion valve faulty Check expansion valve.
Receiver / dryer clogged Check receiver / dryer.
Compressor drive belt loosen or broken Adjust or replace drive belt.
Magnetic clutch faulty Check magnetic clutch.
Compressor faulty Check compressor.
Air in A/C system Replace receiver / dryer, and perform
evacuation and charging.
Air leaking from cooling unit or air duct Repair as necessary.
Heater and ventilation system faulty Check air inlet box (cooling unit), heater
control lever assembly and heater unit
referring to Section 1A.
Blower fan motor faulty Check blower fan motor referring to Sec-
tion 1A.
Excessive compressor oil existing in
A/C systemPull out compressor oil in A/C system cir-
cuit, and replace compressor.
Cool air won’t come
out only intermittentlyWiring connection faulty Repair as necessary.
Expansion valve faulty Check expansion valve.
Excessive moisture in A/C system Replace receiver / dryer, and perform
evacuation and charging.
Magnetic clutch faulty Check magnetic clutch.
Excessive charge of refrigerant Check charge of refrigerant.
Thermal switch faulty Check thermal switch.
Cool air comes out
only at high speedCondenser clogged Check A/C condenser.
Insufficient charge of refrigerant Check charge of refrigerant.
Air in A/C system Replace receiver / dryer, and perform
evacuation and charging.
Compressor drive belt loosen or broken Adjust or replace drive belt.
Compressor faulty Check compressor.
Cool air won’t come
out only at high speedExcessive charge of refrigerant Check charge refrigerant.
A/C evaporator frosted Check A/C evaporator and A/C evaporator
thermistor.
Insufficient velocity of
cooled airA/C evaporator clogged or frosted Check A/C evaporator and A/C evaporator
thermistor.
Air leaking from cooling unit or air duct Repair as necessary.
Blower fan motor faulty Check blower fan motor referring to Sec-
tion 1A.
Wiring or grounding faulty Repair as necessary. Condition Possible Cause Correction
Downloaded from www.Manualslib.com manuals search engine 1B-10 AIR CONDITIONING (OPTIONAL)
Performance Diagnosis
1) Confirm that vehicle and environmental conditions are as fol-
lows.
Vehicle is not exposed to direct sun.
Ambient temperature is within 15 – 35 °C (59 – 95 °F).
2) Make sure that high pressure valve (1) and low pressure
valve (2) of manifold gauge set (3) are firmly closed.
3) Connect high pressure charging hose (4) to high pressure
service valve (5), and connect low pressure charging hose
(6) to low pressure service valve (7).
4) Bleed the air in charging hoses (4), (6) by loosening their
respective nuts on manifold gauge set (3), utilizing the refrig-
erant pressure. When a hissing sound is heard, immediately
tighten nut.
5) Warm up engine to normal operating temperature (engine
coolant temperature at 80 – 90 °C (176 – 194 °F)) and keep
it at specified idle speed. (Radiator cooling fan should not be
working when checking pressure and temperature.)
6) Turn A/C switch ON, and set blower switch at “HI” (3rd posi-
tion), temperature knob at “COOL” air outlet control knob at
“FACE” and fresh / circulation control knob at “CIRCULA-
TION”. (Confirm that A/C compressor and radiator / con-
denser cooling fan are working.)
Keep all windows, doors and engine food open.
Performance diagnosis condition
7) With dry bulb thermometer (1) inserted into center duct air
outlet and another one set near evaporator air inlet, read
temperature indicated on each thermometer. CAUTION:
Do not interchange high and low pressure charging
hoses by mistake.
Ambient temperature 15 – 35 °C (59 – 95 °F)
Engine rpm Keep to 1,500 rpm.
Blower fan motor switch “H” (3rd position)
Temperature control “Cool”
Air outlet control “Face”
Vehicle doors All open
Air inlet door position Recirculation
Downloaded from www.Manualslib.com manuals search engine AIR CONDITIONING (OPTIONAL) 1B-13
CROSSING POINT OF CENTER VENTILATION LOUVER TEMPERATURE AND RECIRCULATION AIR
INLET TEMPERATURE
Detail diagnosis table (Ambient temperature at 30°C (86°F))
Condition Possible Cause Correction
Crossing point is
higher than accept-
able range
(“E” area)Insufficient or excessive charge of refrigerant Check refrigerant pressure
Dirty or bent A/C evaporator fins Clean or repair
Air leakage from cooling (heater) unit or air duct Repair or replace
Malfunctioning, switch over function of door in
cooling (heater) unitRepair or replace
Compressor malfunction Check compressor
Crossing point is
lower than acceptable
range
(“F” area)Insufficient air volume from center duct (Heater
blower malfunction)Check blower motor and fan
Compressor malfunction Check compressor
Condition
Possible Cause Correction MANIFOLD
GAUGEMPa
(kg/cm
2)
(psi)Detail
Lo Hi
0.23 – 0.35
(2.3 – 3.5)
(33 – 50)1.4 – 1.75
(14 – 17.5)
(200 – 249)Normal condition
––
Negative
pressure0.5 – 0.6
(5 – 6)
(71.2 – 85.3)The low pressure side
reads a negative pres-
sure, and the high pres-
sure side reads an
extremely low pressure.
Presence of frost
around tubing to and
from receiver / dryer
and expansion valve.Dust particles or water
droplets are either stuck
or frozen inside expan-
sion valve, preventing the
refrigerant from flowing.Clean expansion valve.
Replace it if it cannot be
cleaned.
Replace receiver / dryer.
Evacuate the A/C sys-
tem and recharge with
fresh refrigerant.
Normal :
0.23 – 0.35
(2.3 – 3.5)
(33 – 50)
↑
↑ ↑ ↑ ↓
↓↓ ↓
Abnormal :
Negative
pressureNormal :
1.4 – 1.75
(14 – 17.5)
(200 – 249)
↑
↑ ↑ ↑ ↓
↓↓ ↓
Abnormal :
0.69 – 0.98
(7 – 10)
(100 – 142)During A/C operation,
the low pressure side
sometimes indicates
negative pressure, and
sometimes normal
pressure. Also high
pressure side reading
fluctuates between the
abnormal and normal
pressure.Expansion valve is frozen
due to moisture in the
system, and temporarily
shuts off the refrigeration
cycle.Replace expansion valve.
Replace receiver / dryer.
Evacuate A/C system
and recharge with fresh
refrigerant.
Downloaded from www.Manualslib.com manuals search engine 1B-16 AIR CONDITIONING (OPTIONAL)
Electronical Diagnosis
Wiring Diagram
[A]: 4WD model 4. Dual pressure switch 9. Thermal switch 14. Circuit fuse box
[B]: 2WD model 5. 4WD controller 10. Ignition switch 15. Main fuse box
1. Blower fan motor 6. Condenser cooling fan motor relay 11. A/C evaporator thermistor 16. Generator
2. Blower fan motor resistor 7. Condenser cooling fan motor 12. ECT sensor 17. ECM
3. Blower fan motor switch and A/C switch 8. Compressor 13. Lighting switch
Downloaded from www.Manualslib.com manuals search engine AIR CONDITIONING (OPTIONAL) 1B-17
A/C System Inspection of ECM and ITS Cir-
cuits
ECM and its circuits can be checked at ECM wiring couplers by
measuring voltage.
Voltage Check
1) Remove ECM from vehicle by referring to “Engine Control
Module” in Section 6E.
2) Connect ECM couplers (1) to ECM (2).
3) Check voltage at each terminal of couplers connected.CAUTION:
ECM cannot be checked by itself. It is strictly prohibited
to connect voltmeter or ohmmeter to ECM with couplers
disconnected from ECM.
NOTE:
Because each terminal voltage is affected by the battery
voltage, confirm that the battery voltage is 11 V or more
when ignition switch is ON.
[A] : Fig. A
[B] : Fig. B
3. E19-3
Downloaded from www.Manualslib.com manuals search engine 1B-18 AIR CONDITIONING (OPTIONAL)
Terminal arrangement of ECM coupler (Viewed from harness side)
1. Blower fan motor 8. Compressor [A]: To “A/C” fuse (25A) in main fuse box
2. Dual pressure switch 9. Thermal switch [B]: To “HEATER” fuse (20A) in circuit fuse box
3. A/C switch 10. Main relay [C]: To “FI” fuse (15A) in main fuse box
4. A/C evaporator thermistor 11. Engine earth [D]: 4WD model
5. ECT sensor 12. Blower fan motor switch [E]: 2WD model
6. Condenser cooling fan motor relay 13. 4WD controller
7. Condenser cooling fan motor 14. ECM
Downloaded from www.Manualslib.com manuals search engine AIR CONDITIONING (OPTIONAL) 1B-19
ECM VOLTAGE VALUES TABLE FOR RELATION OF A/C CONTROL
Terminal Wire CircuitMeasurement
groundNormal value Condition
E18-1 PCompressor
magnet clutch
outputGround to
engine (Fig B)10 – 14 voltBlower fan motor switch and A/C
switch ON with engine running
0 – 1 voltsExcept the above-mentioned condi-
tion with engine running
E18-5 Bl/BMain power sup-
ply for ECMGround to
engine (Fig B)10 – 14 voltsIgnition switch ON with engine
stopped
E18-6 Bl/BMain power sup-
ply for ECMGround to
engine (Fig B)10 – 14 voltsIgnition switch ON with engine
stopped
E18-10 Bl Main relay driveGround to
engine (Fig B)0.5 – 1.2 voltIgnition switch ON with engine
stopped
0 volts Ignition switch OFF
E18-16 G/W A/C switch inputGround to
engine (Fig B)12 – 15 voltsBlower fan motor switch or A/C switch
OFF with engine running
0 – 1 voltBlower fan motor switch and A/C
switch ON with engine running
12 – 15 voltsWithin several seconds after operate
transfer lever between 2WD and 4WD
with above condition
E18-18 P/BCompressor
cooling fan relay
outputGround to
engine (Fig B)0 – 1 voltBlower fan motor switch and A/C
switch ON or engine coolant tempera-
ture at more than 110 °C (230 °F) with
engine running.
12 – 15 voltsExcept the above-mentioned condi-
tion with engine running
E18-20 B/BlSensor ground
for A/C evapora-
torGround to
body (Fig A)–0.5 – 0 volt Engine running
E18-24 Bl/YBlower fan
speed inputGround to
engine (Fig B)0 – 1 voltBlower fan motor switch 2nd or 3rd
with engine running
4 – 7 voltsBlower fan motor switch 1st with
engine running
12 – 15 voltsBlower fan motor switch and A/C
switch OFF with engine running
E19-1 BMain ground for
ECMGround to
engine (Fig A)–0.5 – 1 volt Engine running
E19-2 B/RECM ground for
power circuitGround to
engine (Fig A)–0.5 – 1 volt Engine running
E19-3 B/RECM ground for
power circuitGround to
engine (Fig A)–0.5 – 1 volt Engine running
E19-10 B/BlSensor ground
for ECT sensorGround to
body (Fig A)–0.5 – 1 volt Engine running
Downloaded from www.Manualslib.com manuals search engine AIR CONDITIONING (OPTIONAL) 1B-29
On-Vehicle Service
Service Precaution
When servicing air conditioning system, note the following instructions.
Refrigerant line
Never use heat for bending pipes. When bending a pipe, try to make its bending radius as slight as possible.
Keep internal parts of air conditioning free from moisture and dirt. When disconnecting any line from system,
install a blind plug or cap to the fitting immediately.
When connecting hoses and pipes, apply a few drops of compressor oil to seats of coupling nuts and O-ring.
When tightening or loosening a fitting, use two wrenches, one for turning and the other for support.
Tighten flared nuts by the following specified torque.
Tightening torque (Flared Nut Used for)
8 mm pipe : 13 N·m (1.3 kg-m, 9.5 lb-ft)
12 mm pipe : 23 N·m (2.3 kg-m, 16.6 lb-ft)
14.5 mm pipe : 33 N·m (3.3 kg-m, 23.8 lb-ft)
Route drain hose so that drained water does not make any contact to vehicle components.
Before evacuating and charging refrigerant, replenish specified amount of compressor oil to compressor
suction side by referring to “Replenishing Compressor Oil” in this section.
1. Suction hose:
Apply compressor oil to O-ring.4. Condenser outlet pipe:
Apply compressor oil to O-ring.
2. Discharge hose:
Apply compressor oil to O-ring.5. Expansion valve:
Apply compressor oil to O-ring.
3. Receiver / dryer outlet pipe:
Apply compressor oil to O-ring.6. Dual pressure switch:
Apply compressor oil to O-ring.