PIPE 0992864 - Caterpillar

Illustration 1 g00902051
Dash panel (1) Parking brake switch
Illustration 2 g00902054
Right side view of transmission (2) Transmission oil pressure sensor (obscured)
Illustration 3 g00902055
Left side view of transmission compartment (3) Brake accumulator oil pressure switch - alert indicator (4) Brake accumulator oil pressure switch - brake application
Illustration 4 g00902056
Left side view of transmission compartment (5) Parking brake solenoids (6) Parking brake oil pressure switch
Illustration 5 g00902058
Front view of cab (front cover plate removed) (7) Power Train/Chassis ECMWith the engine start switch in the ON position, 24 volt power is supplied from the batteries via circuit breaker #12, to the transmission oil pressure sensor and the Power Train/Chassis ECM.
Illustration 6 g00902059
Dash panel (8) Parking brake alert indicatorWhen parking brake switch (1) is moved to the ON position, 24 volt power from Power Train/Chassis ECM (7) 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 (6) sends a signal to the Power Train/Chassis ECM. The Power Train/Chassis ECM sends a signal via the CAT Data Link to the Caterpillar Monitoring System. The Caterpillar Monitoring System turns ON parking brake alert indicator (8) .When the engine start switch is in the ON position and the parking brake switch is in the OFF position, the parking brake switch must be cycled to allow the parking brake to disengage.When pressure decreases in the brake system the brake accumulator oil pressure switches will activate. The brake accumulator oil pressure switches then send a signal to the Power Train/Chassis ECM to engage the parking brake.When the oil pressure in the transmission decreases below 230 kPa (25.5 psi), the transmission oil pressure sensor will activate. The transmission oil pressure sensor sends a signal to the Power Train/Chassis ECM. The Power Train/Chassis ECM engages the parking brakes.When the parking brake switch is moved to the OFF position, power from the Power Train/Chassis ECM is supplied to activate the parking brake solenoids. This will allow pressure oil to flow to the wheel brakes to disengage the parking brakes. The parking brake alert indicator will be OFF.
Illustration 7 g00902061
Parking brake circuit