ELECTRICAL TROUBLESHOOTING
TM 5-3805-263-14&P-3
EMS PANEL
PROBLEM B: An Indicator That Must Be ON is NOT ON.
Possible Causes: a. Switch is bad.
b. Wire, in the harness, that goes to the switch, is grounded or shorted
to another wire in the harness that is at ground potential.
c. Operator panel is bad.
TROUBLESHOOTING
With the test switch OFF and the engine OFF, the oil pressure indicator and the
alternator indicator must be ON. If the brake system air pressure is below about 62
psi (430 kPa), this light will be ON. Check these conditions before servicing panel.
If the alternator indicator is NOT ON, replace the operator panel.
If the oil pressure or brake pressure is NOT ON, do the following:
1. Remove the control wire from the switch (sensor). (See Table 2) The indicator must
turn ON.
Indicator Turns ON
Indicator Does Not Turn ON
The switch (or switches) is bad. Replace the switch
The harness has a short, or the operator panel is bad.
(or switches).
Go to Step 2.
2. Put tape on the control that was removed from the switch so that it can not be
grounded to the machine (see Table 2).
Disconnect the harness plug from the operator panel. Use the continuity tester or a
digital multimeter to check for continuity between connections 2 and control wire to be
checked (see Table 2).
TABLE 2
Control Wire Color
Harness Plug Connection
at Switch
Switch
at Operator Panel
GY/R
Oil Pressure
5
Y
Brake Pressure
8
Continuity
No Continuity
There is a ground or a short in the harness. Replace
Replace the operator panel.
the harness.
4-32
