BRACKET-BLOCK CONNECTOR 1153083 - Caterpillar

Engine Start
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Engine start circuitThe components of the engine start circuit are the key start switch, the Power Train Electronic Control Module (Power Train ECM), the Engine Electronic Control Module (Engine ECM), the start relay magnetic switch, the main relay magnetic switch, the electric starter motor solenoid, the electric starter motor, the STIC steering transmission control, the fire suppression control loop receptacle (foam type), and the fire suppression control loop plug (dry powder type).
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(1) Key start switch (2) OFF position (3) ON position (4) START position
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(5) Power Train ECM (6) Main relay magnetic switch
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(7) Engine ECMWith the battery disconnect switch in the ON position, 24 volt power is supplied from the batteries via circuit breaker 14 to Power Train ECM (5) and via circuit breaker 6 to Engine ECM (7) and key start switch (1) .With key start switch (1) in ON position (3), main relay magnetic switch (6) is energized. 24 volt power is supplied from main relay magnetic switch (6) via circuit breaker 6 to Engine ECM (7) and via circuit breaker 14 to Power Train ECM (5).
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(8) Start relay magnetic switch
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(9) Electric starter motor solenoid (10) Electric starter motor
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(11) Transmission control (STIC steering) (12) Transmission direction control switchWhen key start switch (1) is in START position (4), Power Train ECM (5) supplies 24 volt power to start relay magnetic switch (8). Power then returns to Power Train ECM (5) to ground. Power Train ECM (5) will energize start relay magnetic switch (8) when transmission direction control switch (12) is in the NEUTRAL position. When start relay magnetic switch (8) is energized, 24 volt power is supplied to electric starter motor solenoid (9) and to electric starter motor (10). Electric starter motor (10) will begin to crank.ReferenceFor information on the key start switch in the OFF position, refer to Systems Operation, Testing and Adjusting, "Engine Stop".