This sensor monitors hydraulic pressure in the parking brake circuit. It sends an electrical signal to the control unit, which engages or releases the brake based on the pressure state. The sensor threads into the brake valve block; a loss of signal prevents the brake from releasing, leaving the machine immobilized. The original component matches the electrical connector profile and pressure-switching threshold of the factory assembly. On replacement, ensure the sealing washer is replaced and the sensor is torqued to specification.