Theory Of Operation

The Body Control Module (BCM) provides a battery reference voltage on the Brake Fluid Level Signal circuit to the Brake Fluid Level Switch, along with a Ground circuit. The Brake Fluid Level Switch includes an internal diagnostic resistor that is in parallel with the Brake Fluid Level Signal circuit and Ground circuit, which provides resistance to the BCM when the brake fluid level is above the low level indicator. The BCM detects a low brake fluid level when the brake fluid level is below the low level indicator and the Brake Fluid Level Switch closes. When the Brake Fluid Level Switch is closed, the internal diagnostic resistor is bypassed and the reference voltage is pulled low.