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| Illustration 1 | g03816236 |
Power Distribution (1) To terminal "J1-59" engine ECM (2) From pull-up resistor (3) B+ from shutdown status fuse (4) B+ from control fuse (5) B+ from machine fuse (6) Hydraulic filter bypass switch (7) Hydraulic oil temperature sensor (8) Interlock solenoid (9) Propel lever (10) Reverse switch (11) Fault alarm (12) Upper fuse block (13) Display (14) CAN resistor (15) Backup alarm (16) Parking brake switch (17) Neutral start switch (18) Neutral relay number-one (19) Brake relay number-two (20) Brake relay number-one (21) Lower fuse block (22) Backup alarm relay | |
Power Distribution
When the engine start switch is in the ON position, power is available at pull-up resistor (2), shutdown fuse (3), control fuse (4) and machine fuse (5). These fuses provide power to components in the propel system.
Shutdown status fuse (3) provides power to contact "30" and contact "86" of backup alarm relay (22). This fuse is rated at 15 amp.
Control fuse (4) provides power to fault alarm (11), contact "2" of connector "M-C10" on display (13) and contact "30" of neutral relay number-one (18). This fuse is rated at 10 amp.
Machine fuse (5) provides power to neutral start switch (17). This fuse is rated at 7.5 amp.
Parking Brake Switch ON, Propel Lever in NETURAL
With parking brake switch (16) in the ON position, contacts "2" and "3" are closed. In this case, power transfers from contact "3" of the switch to the following locations:
- Parking brake indicator in the switch
- Contact "86" of brake relay number-one (20)
- Contact "86" of brake relay number-two (19)
- Contact "87" of brake relay number-two (19)
When parking brake switch (16) is in the ON position, the parking brake indicator illuminates. In this situation, coils brake relay number-one (20) and brake relay number-two (19) also energize. When brake relay number-one is energized, interlock solenoid (8) cannot be energized. In this case, the parking brake is engaged. The parking brake remains engaged when the parking brake switch is in the ON position, regardless of the position of propel lever.
With parking brake switch (16) in the ON position, contacts "5" and "6" of the switch are also closed. In this situation, the circuit to terminal "J1-59" of engine ECM (1) is complete.
Neutral Start Switch
When propel lever (9) is in the NEUTRAL position, neutral start switch (17) is closed. In this case, power transfers to contact "86" of neutral relay number-one (18). In this case, the coil of neutral relay number-one is energized. When the propel lever is out of the NEUTRAL position, the neutral start switch is open. In this case, the coil of neutral relay number-one cannot be energized.
Parking Brake Switch OFF, Propel Lever in NEUTRAL
When parking brake switch (16) is moved from the ON position to the OFF position while propel lever (9) is in the NEUTRAL position, the parking brake releases.
With parking brake switch (16) in the OFF position, contact "1" and contact "2" are closed. In this case, power transfers to contact "30" of brake relay number-one (20). When the coil of brake relay number-one is not energized, contact "30" and contact "87a" of the relay are closed. In this case, power transfers to the coil of interlock solenoid (8). When this solenoid is energized, the parking brake is released.
When propel lever (9) is moved out of the NEUTRAL position while parking brake switch (16) is in the OFF position, the machine can move.
Parking Brake Switch ON to OFF, Propel Lever Out of NEUTRAL
The parking brake will remain engaged under the following condition. Parking brake switch (16) is moved from the ON position to the OFF position while propel lever (9) is out of the NEUTRAL position.
When propel lever (9) is out of the NEUTRAL position, neutral start switch (17) is opens. In this case, and the coil of neutral relay number-one (18) de-energizes. This action allows power to transfer across contacts "30" and "87a" of neutral relay number-one. This power transfers to contact "30" of brake relay number-two (19) .
When parking brake switch (16) is moved from the ON position to the OFF position, contacts "2" and "3" of the switch open. In this case, power is no longer available at the coils of brake relay number-one (20) and brake relay number-two (19).
Ordinarily, the above situation would cause the coils of brake relay number-one and brake relay number-two to de-energize and the parking brake to release. However, since voltage is available at contact "30" of brake relay number-two, power immediately transfers from contact "87" of the relay to the following locations:
- Contact "86" of brake relay number-one (20)
- Contact "86" of brake relay number-two (19)
In this case, the coil of brake relay number-one (20) and the coil of brake relay number-two (19) remain energized. The parking brake indicator remains illuminated, and the parking brake remains engaged. These conditions are maintained until the propel lever is moved back to the NEUTRAL position.
Backup alarm
When propel lever (9) is in the reverse range, contacts of reverse switch (10) are closed. Under these conditions, the coil of backup alarm relay (22) is energized. When this relay is energized, power from shutdown status fuse (3) transfers across the gate of the relay. Power at contact "87" of the backup alarm relay is transferred to backup alarm (15). In this case, the backup alarm sounds.
Hydraulic Filter Bypass Switch and Oil Temperature Sensor
Hydraulic filter bypass switch (6) is a pressure switch that provides input to contact "5" of connector "M-C10" on display (13). Power transfers from pull-up resistor (2) to the switch. The resistor is rated at 2 kiloohms. When the switch is open, the voltage at the gate of the switch is pulled up to the level of the voltage input. When the switch is closed, the input voltage at the gate of the switch is grounded. When the switch is grounded, the filter bypass alert is shown on the display, and fault alarm (11) sounds.
Hydraulic oil temperature sensor (7) is a resistance-type sensor. Display (13) passively monitors input from this sensor at contact "11" of connector "M-C10". The hydraulic oil temperature sensor is grounded at a frame ground. The display converts the input signal from the sensor into a temperature value. The operator can view the temperature value on the display screen.