What would be indicated if one engine brake head continues to operate after the brake switch is turned off?

When one engine brake head continues to operate after the brake switch has been turned off, it suggests an issue with the hydraulic control system associated with the engine brake. In this scenario, the most likely cause is broken hydraulic control valve springs.

The hydraulic control valve is responsible for routing hydraulic fluid to the engine brake head when the brake is engaged. If the springs within this valve are broken, they may fail to return the valve to its neutral position after the brake switch is turned off. This can cause the valve to remain partially open or stuck, allowing hydraulic pressure to continue flowing to the brake head, thus keeping it engaged even when the switch is off.

Understanding the roles of the various components involved is crucial for diagnosing issues effectively. The clutch switch, solenoid valve, and master piston spring also contribute to the overall functionality of the system, but their failure would typically manifest in different ways, such as engagement issues or lack of activation altogether, rather than causing a single brake head to remain active after deactivation of the switch.