Page 1417 of 2890
G4M0654
18. Pressure Switch (Dual Switch)
Pressure switch is attached to receiver dryer.
A: INSPECTION
1) Remove cap from high-pressure line service valve, and
connect gauge manifold to service valve.
2) Disconnect pressure switch harness connector, and
check pressure switch for proper ON-OFF operation. Use
a circuit tester.
Terminal OperationHigh-pressure side line pressure
kPa (kg/cm2, psi)
High and low pressure
switch
1—2
Turns OFF.Increasing to
2,648±196 (27±2, 384±28)
Decreasing to
177±20 (1.8±0.2, 26±3)
Turns ON.Increasing to
186±29 (1.9±0.3, 27±4)
Decreasing to
1,471
+196
98(15+2
1, 213+28
14)
40
4-7SERVICE PROCEDURE
18. Pressure Switch (Dual Switch)
Page 1418 of 2890
1. Air Conditioning System Diagnosis
41
4-7DIAGNOSTICS
1. Air Conditioning System Diagnosis
Page 1419 of 2890

2. Performance Test Diagnosis
If various conditions caused to other air conditioning
system, the characteristics revealed on manifold gauge
reading are shown in the following:
As to the method of a performance test, refer to the item
of“Performance Test”.
Each shaded area on the following tables indicates a read-
ing of the normal system when the temperature of outside
air is 32.5°C (91°F).
Condition Probable cause Corrective action
INSUFFICIENT REFRIGERANT CHARGE
G4M0673
Insufficient cooling Refrigerant is small, or
leaking a little.1. Perform leak test.
2. Repair leak.
3. Charge system.
Evacuate, as
necessary, and
recharge system.
ALMOST NO REFRIGERANT
G4M0674
No cooling action Serious refrigerant leak.Stop compressor
immediately.
1. Perform leak test.
2. Discharge system.
3. Repair leak(s).
4. Replace receiver
drier if necessary.
5. Check oil level.
6. Evacuate and
recharge system.
FAULTY EXPANSION VALVE
G4M0675
Slight cooling;
Sweating or frosted
expansion valve inlet.Expansion valve
restricts refrigerant flow.
Expansion valve is
clogged.
Expansion valve is
inoperative.
Valve stuck closed.
Thermal bulb has lost
charge.If valve inlet reveals
sweat or frost:
1. Discharge system.
2. Remove valve and
clean it. Replace it if
necessary.
3. Evacuate system.
4. Charge system.
If valve does not oper-
ate:
1. Discharge system.
2. Replace valve.
3. Evacuate and charge
system.
42
4-7DIAGNOSTICS
2. Performance Test Diagnosis
Page 1420 of 2890

Condition Probable cause Corrective action
G4M0676
G4M0677
Insufficient cooling;
Sweated suction line.
No cooling;
Sweating or frosted suc-
tion line.Expansion valve allows
too much refrigerant
through evaporator.
Faulty seal of O-ring in
expansion valve.Check valve for opera-
tion. If suction side does
not show a pressure
decrease, replace valve.
1. Discharge system.
2. Remove expansion
valve and replace
O-ring.
3. Evacuate and
replace system.
AIR IN SYSTEM
G4M0678
Insufficient cooling Air mixed with refriger-
ant in system.1. Discharge system.
2. Replace receiver
drier.
3. Evacuate and charge
system.
MOISTURE IN SYSTEM
G4M0679
After operation for a
while, pressure on suc-
tion side may show
vacuum pressure read-
ing. During this
condition, discharge air
will be warm. As warn-
ing of this, reading
shows 39 kPa (0.4
kg/cm
2, 6 psi) vibration.Drier is saturated with
moisture. Moisture has
frozen at expansion
valve. Refrigerant flow
is restricted.1. Discharge system.
2. Replace receiver
drier (twice if neces-
sary).
3. Evacuate system
completely. (repeat
30-minute evacuating
three times.)
4. Recharge system.
43
4-7DIAGNOSTICS
2. Performance Test Diagnosis
Page 1421 of 2890

Condition Probable cause Corrective action
FAULTY CONDENSER
G4M0680
No cooling action;
Engine may overheat.
Suction line is very hot.Condenser is often
found not functioning
well.Check condenser
cooling fan.
Check condenser for
dirt accumulation.
Check engine cooling
system for overheat.
Check for refrigerant
overcharge.
If pressure remains
high in spite of all
above actions taken,
remove and inspect
the condenser for pos-
sible oil clogging.
HIGH-PRESSURE LINE BLOCKED
G4M0681
Insufficient cooling;
Frosted high-pressure
liquid line.Drier is clogged, or
restriction in high-pres-
sure line.1. Discharge system.
2. Remove receiver
drier or strainer and
replace it.
3. Evacuate and charge
system.
FAULTY COMPRESSOR
G4M0682
Insufficient cooling Internal problem is in
compressor, or dam-
aged gasket and valve.1. Discharge system.
2. Remove and check
compressor.
3. Repair or replace
compressor.
4. Check oil level.
5. Replace receiver
drier.
6. Evacuate and charge
system.
44
4-7DIAGNOSTICS
2. Performance Test Diagnosis
Page 1422 of 2890
3. Blower Motor Diagnosis
45
4-7DIAGNOSTICS
3. Blower Motor Diagnosis
Page 1423 of 2890
4. Compressor Diagnosis
46
4-7DIAGNOSTICS
4. Compressor Diagnosis
Page 1424 of 2890
5. Compressor Clutch Diagnosis
Compressor clutch is not engaged.
Check both 10 A fuse for A/C.
Fuse O.K. Fuse blown
Determine cause of blown fuse. Replace faulty part(s)
and fuse.
Does 12 volts exist in control panel connector (R/B)?
Ye s
No
Faulty harness
Does 12 volts exist in control panel connector (B/W)?
Ye s
No
Faulty A/C switch
Does 12 volts exist in dual pressure switch connector
(G/Y)?
Ye s
No
Faulty harness
Does 12 volts exist in dual pressure switch connector
(Br/Y)?
Ye s
No
Faulty dual pressure switch
Does 12 volts exist in A/C relay connector (Br/R) and
(W)?
Ye s
No
Faulty harness
Does 12 volts exist in A/C relay connector (R/W)?
Ye s
No
Does 0 volts exist in A/C relay connector (Br/Y)?
Ye s N o
Faulty A/C relay
ToB
Does 12 volts exist in thermoswitch connector (R/W)?
Ye s
No
Faulty harness
Does 12 volts exist in thermoswitch connector (L/R)?
Ye s
No
Faulty thermoswitch
ToA
47
4-7DIAGNOSTICS
5. Compressor Clutch Diagnosis