Theory Of Operation
WARNING: This page is about a different car, the 2016 Dodge Journey and 2015 Dodge Journey. However, it is still accessible from the selected car via links, so may be relevant.
The Body Control Module (BCM) provides a reference voltage on the brake fluid level signal circuit through a pull-up resistor that is connected to battery voltage. The Brake Fluid Level Switch switches the brake fluid level signal circuit to ground when the fluid level is low. A diagnostic resistor internal to the switch is placed in parallel with the switch.