Theory Of Operation
WARNING: This page is about a different car, the 2020 Jeep Renegade. 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. 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 Brake Fluid Level Switch, is placed in parallel with the switch.