Final answer:
To troubleshoot the system, the student should take a voltage reading across terminals 2 and 3. It will help determine if there is a problem with the burner motor.
Step-by-step explanation:
The student should take a voltage reading across terminals 2 and 3 to further troubleshoot the system. In a series circuit, the voltage across each component is the same, so measuring the voltage at these terminals can help determine if there is a problem with the burner motor. If there is no voltage difference across these terminals, it indicates that the burner motor is not receiving the necessary voltage for operation.