ELECTRICAL TROUBLESHOOTING
TM 5-3805-263-14&P-3
INDIVIDUAL CIRCUIT DESCRIPTION
2. Indicator and Master Fault Light
A. Engine Coolant Temperature
The engine coolant temperature circuit has a normally closed 7N9785
Temperature Switch that opens if the coolant temperature goes up to 2250F (1070C).
If the switch opens, the coolant temperature indicator on the operator panel flashes
ON and OFF. The operator panel also sends current to make the master fault light
flash ON and OFF. The circuit for the engine coolant temperature switch connects to
contact 6 of the operator panel. Contact 11 of the operator panel goes to the master
fault light.
Figure 3. Engine Coolant Temperature Circuit
B. Hydraulic Oil Temperature
The hydraulic oil temperature circuit has a normally closed 3T190 Temperature
Switch that opens if the oil temperature goes up to 1900 F (880C). If the switch
opens, the hydraulic oil temperature indicator on the operator panel flashes ON and
OFF. The operator panel also sends current to make the master fault light flash ON
and OFF. The hydraulic oil temperature switch circuit connects to contact 4 of the
operator panel. Contact 11 of the operator panel goes to the master fault light.
Figure 4. Hydraulic Oil Temperature Circuit
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