PLUG GP-GLOW 4N2008 - Caterpillar

Illustration 1 g01231512
Parking brake circuitThe components of the parking brake circuit are the parking brake switch, the transmission oil pressure sensor, the transmission oil pressure alert indicator, the parking brake oil pressure switch, the parking brake alert indicator, the parking brake solenoids, the Power Train Electronic Control Module (Power Train ECM), the Caterpillar Monitoring System ECM, the brake accumulator oil pressure switch for brake application and the brake accumulator oil pressure alert indicator.
Illustration 2 g01003585
(1) Parking brake switch
Illustration 3 g01224854
(2) Transmission oil pressure sensor
Illustration 4 g01245526
(3) Parking brake oil pressure switch (4) Parking brake control valve
Illustration 5 g01224855
View of parking control valve (5) Parking brake solenoids
Illustration 6 g01236910
(6) Power Train ECM
Illustration 7 g01240949
(7) Parking brake alert indicator (8) Brake accumulator oil pressure alert indicator (9) Transmission oil pressure alert indicator
Illustration 8 g01224856
(10) Brake accumulator oil pressure switch for alert indicator (11) Brake accumulator oil pressure switch for brake applicationWith the key start switch in the ON position, 24 volt power is supplied from the batteries via circuit breaker 14 to Power Train ECM (6) and transmission oil pressure sensor (2) and via circuit breaker 13 to the Caterpillar Monitoring System ECM.When parking brake switch (1) is moved to the ON position, 24 volt power from Power Train ECM (6) to parking brake solenoids (5) is interrupted. The pressure oil in the wheel brakes is returned to the hydraulic tank and the parking brake is engaged. In this condition, parking brake oil pressure switch (3) sends a signal to Power Train ECM (6). Power Train ECM (6) sends a signal to the Caterpillar Monitoring System ECM. The Caterpillar Monitoring System ECM turns on parking brake alert indicator (7) .If the oil pressure in the service brake system decreases below a pre-determined value, contacts in brake accumulator oil pressure switch for alert indicator (10) will open. Switch (10) sends a signal to the Caterpillar Monitoring System ECM. The Caterpillar Monitoring System ECM will then turn on brake accumulator oil pressure alert indicator (8) on the Caterpillar Monitoring System display. If the oil pressure decreases further, contacts in brake accumulator oil pressure switch for brake application (11) will open. Switch (11) sends a signal to Power Train ECM (6). Power Train ECM (6) will de-energize parking brake solenoids (5). The parking brake will engage.If the oil pressure in the transmission decreases below a pre-determined value, this change is sensed by transmission oil pressure sensor (2). A Pulse Width Modulated (PWM) signal is sent to Power Train ECM (6). Power Train ECM (6) sends the signal to the Caterpillar Monitoring System ECM to turn on transmission oil pressure alert indicator (9). If the transmission oil pressure decreases further Power Train ECM (6) will de-energize parking brake solenoids (5). The parking brake will engage.When parking brake switch (1) is moved to the OFF position, power from Power Train ECM (6) is supplied to energize parking brake solenoids (5). This will allow pressure oil to flow to the wheel brakes to disengage the parking brake. Parking brake alert indicator (7) will be off.