Brake Fluid Level Switch Circuit
WARNING: This page is about a different car, the 2004 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
This switch signals the CAB for a hydraulic fluid problem. The antilock system uses input from the brake fluid level switch when activated. A low brake fluid condition in the master cylinder will close the switch circuit and read 0 volts. When the brake fluid level is at specifications, the switch will open and circuit sense voltage will read 5 volts. This signal tells the CAB if there is enough brake fluid in the master cylinder to have an antilock operation.
The brake fluid level switch is located in the master cylinder reservoir with a 10k resistor. The switch is a Hall effect design and uses a float to determine level.