What is a common troubleshooting step when a unit fails to start?

A common troubleshooting step when a unit fails to start is to check for electrical supply and ensure all safety switches are engaged. This is vital because many components of the unit rely on a stable and adequate electrical supply to operate correctly. If there is an issue, such as a blown fuse, disconnected wiring, or tripped safety switches, the unit will not receive the power it needs to start. Engaging all safety switches is crucial as these are designed to prevent operation when certain conditions are not met, thereby ensuring the safety of both the equipment and its operators.

In contrast, immediately replacing the compressor without investigating the underlying cause may not be effective or necessary, as the issue could lie elsewhere in the electrical or control systems. Inspecting the cargo area for blockages is also less relevant to starting issues, as it pertains more to operational efficiency rather than the initial functionality of the unit. Measuring refrigerant temperature is important when diagnosing cooling efficiency but does not directly pertain to the starting process of the unit. Thus, ensuring electrical supply and safety switch engagement is the most logical first step in troubleshooting a unit that fails to start.