Brake Booster Pump Circuit Description RH Drive

The power brake booster pump supplies the hydraulic pressure needed for power assist braking. The power brake booster system supplies hydraulic pressure to the hydraulic brake accumulator after the accumulator is discharged. Battery positive voltage (B+) is supplied at all times to the power brake booster pump relay via CKT 642 (RED). With the ignition switch in the ON position, battery positive voltage (B+) is supplied to the power brake booster pump relay via CKT 139 (PNK). When more hydraulic pressure is needed in the accumulator, the power brake booster pressure switch will close. This grounds the power brake booster pump relay via CKT 1809 (DK BLU), energizing the relay. The relay switch closes and supplies battery positive voltage (B+) to the power brake booster pump motor via CKT 173 (PNK). The power brake booster pump motor and power brake booster pressure switch are permanently grounded to G100 via CKT 1550 (BLK). When the power brake booster pump motor has power and ground, it runs to supply the additional hydraulic pressure to the accumulator.