Toyota T100 1996 Service Manual page 1977

AC−6
Condition: Does not cool (Cools from time to time in some cases)
Symptom seen in
refrigeration system
S Vacuum indicated on low pres-
sure side, very low pressure indi-
cated on high pressure side
S Frost or dew seen on piping be-
fore and after receiver/ drier or ex-
pansion valve
Condition: Insufficient cooling
Symptom seen in
refrigeration system
S Pressure too high on both low
and high pressure sides
S No air bubbles seen through the
sight glass even when the engine
rpm is lowered
1996 TOYOTA T100 (RM449U)
AIR CONDITIONING
Probable cause
S Refrigerant flow obstructed by
moisture or dirt in refrigeration sys-
tem
S Refrigerant flow obstructed by
gas leakage from expansion valve
Probable cause
S Unable to develop sufficient per-
formance due to excessive refrig-
erant in system
S Insufficient cooling of condenser
− AIR CONDITIONING SYSTEM
(5) Refrigerant does not circulate
Diagnosis
Refrigerant does not circulate
(6) Refrigerant overcharged or insufficient cooling of
condenser
Diagnosis
S Excessive refrigerant in
cycle → refrigerant overcharged
S Condenser cooling
insufficient → condenser fins
clogged of cooling fn faulty
Remedy
(1) Check expansion valve
(2) Clean out dirt in expansion
valve by blowing with air
(3) Replace receiver
(4) Evacuate air and charge new
refrigerant to proper amount
(5) For gas leakage from expan-
sion valve, replace expansion
valve
Remedy
(1) Clean condenser
(2) Check cooling fan with fluid
coupling operation
(3) If (1) and (2) are in normal
state, check amount of refrigerant
Charge proper amount of refriger-
ant
I01449
I01390