Which technician is correct about the function of the pressure differential switch and combination valve?

The function of the pressure differential switch and combination valve is critical in the operation of a vehicle's braking system. The pressure differential switch is designed to monitor the differences in hydraulic pressure between the two brake circuits. If a significant pressure drop occurs, typically due to a leak or failure in one circuit, the switch activates to alert the driver, often through a dashboard light. This ensures that the driver is aware of potential braking issues, allowing for timely service.

The combination valve (which often integrates a pressure differential switch) plays a role in both the distribution of brake fluid and in the actuation of a warning light, as well as providing some form of pressure modulation. It can also have components that manage brake balance and anti-lock braking system (ABS) functions in more advanced systems.

Given that both technicians understand these functions and correctly describe the relationship and roles of the pressure differential switch and combination valve in the brake system, it logically follows that both of them are correct in their statements regarding these components. Their knowledge encompasses their primary roles in vehicle safety and operation, aligning with the operative principles of braking systems.