Normal Operation
When the parking brake is applied, circuit (R/Y) to the smart junction box (SJB) is grounded by the parking brake switch through circuit (B). The SJB receives the ground signal and grounds circuit (V/W) to the instrument cluster to illuminate the brake warning indicator. When the brake fluid level is low, the brake fluid level switch closes, sending a ground signal to the anti-lock brake system (ABS) module. The ABS module, in turn, provides a ground signal to the instrument cluster through circuit (LB/B) to illuminate the brake warning indicator.