Komatsu Galeo PC138US-8 Shop Manual page 695

SEN02467-00
Trouble (4) Air is not cooled (Cooling performance is insufficient).
Related
information
Defective compressor relay
1
(Internal disconnection)
2 Defective internal air sensor
Defective high and low pres-
3
sure switches
Defective compressor clutch
4
(Internal defect)
Defective compressor (Inter-
5
nal defect)
Possible causes
and standard
value in normal
state
Disconnection in wiring har-
ness (Disconnection in wiring
6
or defective contact in con-
nector)
Ground fault in wiring har-
7 ness (Short circuit with GND
circuit)
Defective air conditioner con-
8
troller
Defective air conditioner sys-
9
tem
42
Cause Standard value in normal state/Remarks on troubleshooting
a Prepare with starting switch OFF, then carry out troubleshoot-
a Prepare with starting switch OFF, then turn starting switch ON
chassis ground
Internal air sensor may be defective. Carry out troubleshooting for
Abnormality in internal air sensor.
High and low pressure switches may be defective. Carry out trou-
bleshooting for "Abnormality in refrigerant".
Compressor clutch may be defective. Check it directly.
Compressor may be defective. Check it directly.
a Prepare with starting switch OFF, then carry out troubleshoot-
Wiring harness between F01-10 – fuse in
unit – R21 (female) (1)
Wiring harness between R21 (female) (3) –
AC
W
Wiring harness between F01-11 – R21
(female) (4)
Wiring harness between R21 (female) (2) –
AC02 (female) (1)
a Prepare with starting switch OFF, then carry out troubleshoot-
Wiring harness between R21 (female) (3) –
AC
W
Wiring harness between R21 (female) (2) –
AC02 (female) (1)
If causes 1 – 7 are not detected, air conditioner controller may be
defective. (Since trouble is in system, troubleshooting cannot be
carried out.)
If causes 1 – 7 are not detected, air conditioner system may be
defective. See Machine Component Volume of Shop Manual, Air
conditioner, Troubleshooting.
ing without turning starting switch ON (coil side).
R21 (male)
Between (1) – (3)
and carry out troubleshooting (contact side).
R21 Air conditioner switch
Between (2) –
Cooling position
ing without turning starting switch ON.
(wiring side) (35)
ing without turning starting switch ON.
(wiring side) (35)
40 Troubleshooting
Resistance
140 – 340 z
Voltage
20 – 30 V
Resis-
Max. 1 z
tance
Resis-
Max. 1 z
tance
Resis-
Max. 1 z
tance
Resis-
Max. 1 z
tance
Resis-
Min. 1 Mz
tance
Resis-
Min. 1 Mz
tance
PC138US, USLC-8