Komatsu PC200-8M0 Shop Manual page 1219

100 Air conditioner
Troubleshooting for compressor and refrigerant system (Air is not cooled)
Cause
Open circuit in wiring har-
4
ness
Ground fault in wiring har-
5 ness
(contact with ground circuit)
Short circuit in wiring har-
6
ness
Defective air conditioner
7
controller
Defective machine monitor
8
(defective switch)
Defective air conditioner
9
unit
PC200, 200LC, 220, 220LC-8M0
Procedure, measuring location, criteria and remarks
1. Turn starting switch to OFF position.
2. Disconnect connector R21 and carryout troubleshooting without turning starting
switch ON.
a Ensure that test result for cause 2 (air conditioner compressor is normal) is normal.
Between connector R21 (female) (5) and F01-11
(Dual pressure switch is turned ON)
Between connector R21 (female) (3) and chassis
Resistance ground
(Air conditioner compressor coil resistance)
Between F01-10 and AC01 (female) (4)
a Relay coil resistance
a If the fuse is not blown, skip troubleshooting.
1. Turn starting switch to OFF position.
2. Disconnect connectors AC03 and R21, and connect a T-adapter to the female side
of AC03.
Resistance Between AC03 (female) (1) and chassis ground
1. Turn starting switch to OFF position.
2. Disconnect connectors AC01, AC02, and R21.
a Ensure that test result for cause 2 is normal.
Between wiring harness side (2) of connector R21 and
Resistance
AC02 (female) (2), (3), and (4)
1. Turn starting switch to OFF position.
2. Disconnect connector R21.
3. Turn starting switch to ON position.
4. Display the air conditioner operation screen on the machine monitor and press the
A/C switch.
Voltage Between connector R21 (female) (2) and ground
1. Turn starting switch to ON position.
2. Display the air conditioner operation screen on the machine monitor.
Press A/C switch.
If no failure is found by above checks, air conditioner unit may be defective.
SEN06151-00
Max. 1 z
Approx. 15 z
300 – 500 z
Min. 1 Mz
Min. 1 Mz
Max. 1 V
"A/C ON" is displayed
61
80-100