How is the dashboard indicator light check performed?

The correct approach for performing the dashboard indicator light check involves ensuring that all warning lights illuminate when the ignition is turned on. This step is critical as it verifies that the bulbs are functional and provides a preliminary indication that the vehicle's dashboard warning systems are working correctly. When the ignition key is turned to the "on" position (without starting the engine), all warning lights, including the check engine light, oil pressure light, battery light, and others, should come on momentarily. This provides the driver with an assurance that these indicators can illuminate when necessary, signaling potential issues while driving.

In contrast, checking all lights while driving is not practical for diagnosing dashboard warnings and doesn’t ensure that the warning lights function properly when needed. Testing each light individually is more time-consuming and unnecessary for a preliminary check, while only checking the turn signal lights does not address the various other important warning indicators that could affect vehicle safety and performance. Therefore, confirming that all warning lights illuminate with the ignition on is the most effective and efficient method to assess the readiness of the dashboard warning systems.