Which item must be working properly during an in-cab inspection?

During an in-cab inspection, it's essential that all gauges and indicators are functioning correctly. This is because each gauge plays a critical role in monitoring different aspects of the vehicle's operation, such as speed, fuel level, engine temperature, and oil pressure. Properly functioning gauges and indicators ensure that the driver is aware of the vehicle's condition and can identify any potential issues before they lead to a breakdown or unsafe driving situation.

For instance, if the engine temperature gauge is malfunctioning, the driver might not realize that the engine is overheating, which could cause significant damage. Similarly, if the fuel gauge is faulty, it could lead to running out of fuel unexpectedly. Thus, checking that all gauges and indicators work properly is vital for safe vehicle operation. The focus on a comprehensive inspection reflects the importance of being fully aware of the vehicle's status throughout the drive.