E-17 Air Conditioner Does Not Operate Or Stop - Komatsu WA250-6 Shop Manual

SEN03848-00

E-17 Air conditioner does not operate or stop

Contents of
Air conditioner does not operate or stop.
trouble
• The following is troubleshooting applicable only to the power supply and GND circuit between the air
Related
conditioner and operator's cab. For troubleshooting of the air conditioner unit, see the Shop Manual
information
for the air conditioner.
Defective No.1 and No.2 fuses
of fuse box (FS2) or defective
1 5A and 15A fuses of the main
circuit in the air conditioner
unit.
Grounding fault in power
2 supply wiring harness
(Contact with ground circuit)
Possible
causes and
standard value
in normal state
Defective A/C control panel
power supply and disconnec-
3 tion of GND wring harness
(disconnection or defective
contact in connector)
70
40-400
Causes
If the fuse is burn, the circuit probably has a grounding fault, etc.
(See cause 2.)
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
• When fuse No. 1 of fuse box (FS2) is blown
Wiring harness between fuse No. 1 of fuse
box A – 5A fuse of air conditioner main cir-
cuit, – 15A fuse in the air conditioner and
ground
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
• When fuse No. 1 of fuse box (FS2) is broken
Wiring harness between fuse No. 1 of fuse
box A – compressor clutch relay and ground
Wiring harness between compressor clutch
relay – E10 (female) (2) and ground
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
• When 5A fuse of the air conditioner unit main circuit is broken
Wiring harness between 5A fuse of air condi-
tioner unit main circuit – C48 (female) (7), –
pressure switch, – blower OFF relay primary
side and ground
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
• When 15A fuse of the air conditioner unit is broken
Wiring harness between 15A fuse of air con-
ditioner unit – blower OFF relay and ground
Wiring harness between blower OFF relay –
blower motor and ground
a Prepare with starting switch OFF, then turn starting switch ON
and carry out troubleshooting.
Between (7) and (1)
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between fuse No. 1 of fuse
box (FS2) – C48 (female) (7)
Wiring harness between C48 (female) (1) –
ground
400 Troubleshooting of electrical system (E-mode)
E-17 Air conditioner does not operate or stop
Standard value in normal state/Remarks on troubleshooting
C48 Starting switch
Resis-
tance
Resis-
tance
Resis-
tance
Resis-
tance
Resis-
tance
Resis-
tance
Voltage
ON 20 – 30 V
OFF Max. 1 V
Resis-
tance
Resis-
tance
WA250, 250PZ-6
1
Min.
1 Mz
Min.
1 Mz
Min.
1 Mz
Min.
1 Mz
Min.
1 Mz
Min.
1 Mz
Max. 1 z
Max. 1 z