OPERATOR'S STATION
TM 5-3805-263-14&P-3
PROBLEM C: An Indicator That Must Be OFF, is ON.
Possible Causes: a.
Bad switch (sensor).
b.
Bad ground wire to switch (broken wire or bad connection).
c.
Bad control wire to switch (broken wire or bad connection).
d.
Bad operator panel.
TROUBLESHOOTING
Coolant Temperature,
Hydraulic Oil Temperature
1. Remove the control wire from the switch (sensor) and put it to machine ground (See
TABLE 3). The indicator must turn OFF.
TABLE 3
Control Wire Color
Harness Plug Connection
at Switch
Switch
at Operator Panel
R/W
Oil Pressure
6
Y/PU
Hydraulic Oil Temperature
4
Indicator Turns ON
Indicator Does Not Turn ON
Either the switch or the ground is bad. Go to Step 2.
There is either an open wire in a harness, or the
operator panel is bad. Go to Step 3.
2. Check for continuity across the switch with a continuity tester or a digital multimeter.
Continuity
No Continuity
If there is continuity across the switch, then the
Replace the switch (sensor).
ground for the switch is bad. Replace the harness or
connect another ground wire to the switch.
3. Check for continuity through harnesses from the switch to the operator panel.
Fasten the control wire for the switch to machine ground. Disconnect the harness
plug from the operator panel and check for continuity at the plug connection that is for
the switch that is grounded (See TABLE 3). Use a continuity tester or a digital
Continuity
No Continuity
Replace the operator panel.
Use the electrical schematic or simplified schematic
to check through each harness between the switch
and the operator panel, until the one with the broken
wire is found. Replace the harness.
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