Final answer:
The pressure differential switch controls the flow of hydraulic fluid in the braking system based on the pressure difference between the master cylinder and the wheel cylinders.
Step-by-step explanation:
The purpose of the pressure differential switch in the braking system is to control the flow of hydraulic fluid to the wheel cylinders. It is responsible for sensing the pressure difference between the master cylinder and the wheel cylinders. When the pressure difference exceeds a certain threshold, the switch activates and allows the fluid to flow, applying the brakes.
For example, when the driver presses the brake pedal, the force is increased by the lever and hydraulic system, creating pressure in the master cylinder. The pressure differential switch detects this pressure and allows the hydraulic fluid to flow to the wheel cylinders, generating the necessary force to apply the brakes evenly on all wheels.